HERWIG fortran code to be used with THerwig and AliGenHerwig
authormorsch <morsch@f7af4fe6-9843-0410-8265-dc069ae4e863>
Mon, 15 Jul 2002 17:07:47 +0000 (17:07 +0000)
committermorsch <morsch@f7af4fe6-9843-0410-8265-dc069ae4e863>
Mon, 15 Jul 2002 17:07:47 +0000 (17:07 +0000)
HERWIG/HERWIG61.INC [new file with mode: 0644]
HERWIG/HERWIG6100.f [new file with mode: 0644]
HERWIG/Makefile [new file with mode: 0644]
HERWIG/herwig59.txt [new file with mode: 0644]
HERWIG/herwig61.txt [new file with mode: 0644]
HERWIG/herwig6_address.c [new file with mode: 0644]
HERWIG/herwig6_called_from_cc.f [new file with mode: 0644]
HERWIG/herwig6_common_block_address.f [new file with mode: 0644]
HERWIG/libherwig.pkg [new file with mode: 0644]
HERWIG/main.c [new file with mode: 0644]

diff --git a/HERWIG/HERWIG61.INC b/HERWIG/HERWIG61.INC
new file mode 100644 (file)
index 0000000..5d0e356
--- /dev/null
@@ -0,0 +1,217 @@
+C          ****COMMON BLOCK FILE FOR HERWIG VERSION 6.1****
+C
+C ALTERATIONS: Layout completely overhauled for 5.9
+C
+C
+C New common blocks added for version 6.1:
+C              HWCLUS,HWSUSY,HWRPAR,HWMINB
+C
+C New variables added for version 6.1:
+C              OMHMIX,ET2MIX,PH3MIX,IOP4JT,NPRFMT,
+C              PRNDEF,PRNTEX,PRNWEB,EFFMIN,GCUTME,
+C              IOP4JT,NPRFMT                       see HWPRAM
+C              Y4JT,DURHAM                         see HWHARD
+C              QORQQB,QBORQQ                       see HWPROP
+C              NRECO                               see HWUCLU
+C              TXNAME                              see HWUNAM
+C              PPCL,NCL,IDCL                       see HWCLUS
+C              TANB,ALPHAH,COSBPA,SINBPA,COSBMA,
+C              SINBMA,COSA,SINA,COSB,SINB,COTB,
+C              ZMIXSS,ZMXNSS,ZSGNSS,LFCH,RFCH,
+C              SLFCH,SRFCH,WMXUSS,WMXVSS,WSGNSS,
+C              QMIXSS,LMIXSS,THETAT,THETAB,THETAL,
+C              ATSS,ABSS,ALSS,MUSS,FACTSS,GHWWSS,
+C              GHZZSS,GHDDSS,GHUUSS,GHWHSS,GHSQSS,
+C              XLMNSS,RMMNSS,IMSSM,SENHNC,
+C              SSPARITY,SUSYIN                     see HWSUSY
+C              LAMDA1,LAMDA2,LAMDA3,HRDCOL,RPARTY,
+C              COLUPD                              see HWRPAR
+C              PMBN1,PMBN2,PMBN3,PMBK1,PMBK2,
+C              PMBM1,PMBM2,PMBP1,PMBP2,PMBP3       see HWMINB
+C
+C New parameters added for version 6.1:
+C              NMXCL
+C
+C Parameter NMXRES raised to 500
+C
+C Scalar variables changed to arrays of size 2:
+C              CLSMR,PSPLT,CLDIR                   see HWPRAM
+C
+      IMPLICIT NONE
+      DOUBLE PRECISION ZERO,ONE,TWO,THREE,FOUR,HALF
+      PARAMETER (ZERO =0.D0, ONE =1.D0, TWO =2.D0,
+     &           THREE=3.D0, FOUR=4.D0, HALF=0.5D0)
+C
+      DOUBLE PRECISION
+     & ACCUR,AFCH,ALPFAC,ALPHEM,ANOMSC,ASFIXD,AVWGT,B1LIM,BETAF,BRFRAC,
+     & BRHIG,BTCLM,CAFAC,CFFAC,CLDKWT,CLMAX,CLPOW,CLQ,CLSMR,CMMOM,COSS,
+     & COSTH,CSPEED,CTHRPW,CTMAX,DECPAR,DECWT,DISF,DKLTM,EBEAM1,EBEAM2,
+     & EMLST,EMMAX,EMMIN,EMPOW,EMSCA,ENHANC,ENSOF,EPOLN,ETAMIX,EVWGT,
+     & EXAG,F0MIX,F1MIX,F2MIX,GAMH,GAMMAX,GAMW,GAMWT,GAMZ,GAMZP,GCOEF,
+     & GEV2NB,GEV2MM,GPOLN,H1MIX,HBAR,HARDST,OMEGA0,PBEAM1,PBEAM2,PDIQK,
+     & PGSMX,PGSPL,PHEP,PHIMIX,PHIPAR,PHOMAS,PIFAC,PLTCUT,PPAR,PPOLN,
+     & PRECO,PRSOF,PSPLT,PTINT,PTMAX,PTMIN,PTPOW,PTRMS,PXRMS,PWT,Q2MAX,
+     & Q2MIN,Q2POW,Q2WWMN,Q2WWMX,QCDL3,QCDL5,QCDLAM,QDIQK,QEV,QFCH,QG,
+     & QLIM,QSPAC,QV,QWT,REPWT,RESN,RHOHEP,RHOPAR,RLTIM,RMASS,RMIN,
+     & RSPIN,SCABI,SINS,SNGWT,SWEIN,SWTEF,SUD,THMAX,TLOUT,TMTOP,TMNISR,
+     & TQWT,VCKM,VFCH,VGCUT,VHEP,VMIN2,VPAR,VPCUT,VQCUT,VTXPIP,VTXQDK,
+     & WBIGST,WGTMAX,WGTSUM,WHMIN,WSQSUM,XFACT,XLMIN,XMIX,XMRCT,XX,
+     & XXMIN,YBMAX,YBMIN,YJMAX,YJMIN,YMIX,YMRCT,YWWMAX,YWWMIN,ZBINM,
+     & ZJMAX,ZMXISR,Y4JT,EFFMIN,PPCL,
+     & TANB,ALPHAH,COSBPA,SINBPA,COSBMA,SINBMA,COSA,SINA,COSB,SINB,COTB,
+     & ZMIXSS,ZMXNSS,ZSGNSS,LFCH,RFCH,SLFCH,SRFCH, WMXUSS,WMXVSS,WSGNSS,
+     & QMIXSS,LMIXSS,THETAT,THETAB,THETAL,ATSS,ABSS,ALSS,MUSS,FACTSS,
+     & GHWWSS,GHZZSS,GHDDSS,GHUUSS,GHWHSS,GHSQSS,
+     & XLMNSS,RMMNSS,IMSSM,SENHNC,SSPARITY,LAMDA1,LAMDA2,LAMDA3,
+     & PMBN1,PMBN2,PMBN3,PMBK1,PMBK2,PMBM1,PMBM2,PMBP1,PMBP2,PMBP3,
+     & OMHMIX,ET2MIX,PH3MIX,GCUTME
+C
+      INTEGER
+     & CLDIR,IAPHIG,IBRN,IBSH,ICHRG,ICO,IDCMF,IDHEP,IDHW,IDK,IDKPRD,IDN,
+     & IDPAR,IDPDG,IERROR,IFLAV,IFLMAX,IFLMIN,IHPRO,IMQDK,INHAD,INTER,
+     & IOPDKL,IOPHIG,IOPREM,IPART1,IPART2,IPRINT,IPRO,IPROC,ISLENT,
+     & ISPAC,ISTAT,ISTHEP,ISTPAR,JCOPAR,JDAHEP,JDAPAR,JMOHEP,JMOPAR,
+     & JNHAD,LNEXT,LOCN,LOCQ,LRSUD,LSTRT,LWEVT,LWSUD,MAPQ,MAXER,MAXEV,
+     & MAXFL,MAXPR,MODBOS,MODMAX,MODPDF,NBTRY,NCLDK,NCOLO,NCTRY,NDKYS,
+     & NDTRY,NETRY,NEVHEP,NEVPAR,NFLAV,NGSPL,NHEP,NME,NMODES,NMXCDK,
+     & NMXDKS,NMXHEP,NMXJET,NMXMOD,NMXPAR,NMXQDK,NMXRES,NMXSUD,NPAR,
+     & NPRODS,NQDK,NQEV,NRES,NRN,NSPAC,NSTRU,NSTRY,NSUD,NUMER,NUMERU,
+     & NWGTS,NZBIN,SUDORD,IOP4JT,HRDCOL,NMXCL,NCL,IDCL,NPRFMT,NRECO
+C
+      LOGICAL
+     & AZSOFT,AZSPIN,BGSHAT,BREIT,CLRECO,COLISR,DKPSET,FROST,FSTEVT,
+     & FSTWGT,GENEV,GENSOF,HARDME,HVFCEN,MAXDKL,MIXING,NOSPAC,NOWGT,
+     & PRNDEC,PIPSMR,PRVTX,RSTAB,SOFTME,TMPAR,TPOL,USECMF,VTOCDK,VTORDK,
+     & ZPRIME,RPARTY,COLUPD,PRNDEF,PRNTEX,PRNWEB,DURHAM,SUSYIN,
+     & QORQQB,QBORQQ
+C
+      CHARACTER*4
+     & BDECAY
+      CHARACTER*8
+     & PART1,PART2,RNAME
+      CHARACTER*20
+     & AUTPDF
+      CHARACTER*37
+     & TXNAME
+C
+C New standard event common
+      PARAMETER (NMXHEP=2000)
+      COMMON/HEPEVT/NEVHEP,NHEP,ISTHEP(NMXHEP),IDHEP(NMXHEP),
+     & JMOHEP(2,NMXHEP),JDAHEP(2,NMXHEP),PHEP(5,NMXHEP),VHEP(4,NMXHEP)
+C
+C Beams, process and number of events
+      COMMON/HWBEAM/IPART1,IPART2
+      COMMON/HWBMCH/PART1,PART2
+      COMMON/HWPROC/EBEAM1,EBEAM2,PBEAM1,PBEAM2,IPROC,MAXEV
+C
+C Basic parameters (and quantities derived from them)
+      COMMON/HWPRAM/AFCH(16,2),ALPHEM,B1LIM,BETAF,BTCLM,CAFAC,CFFAC,
+     & CLMAX,CLPOW,CLSMR(2),CSPEED,ENSOF,ETAMIX,F0MIX,F1MIX,F2MIX,GAMH,
+     & GAMW,GAMZ,GAMZP,GEV2NB,H1MIX,PDIQK,PGSMX,PGSPL(4),PHIMIX,PIFAC,
+     & PRSOF,PSPLT(2),PTRMS,PXRMS,QCDL3,QCDL5,QCDLAM,QDIQK,QFCH(16),QG,
+     & QSPAC,QV,SCABI,SWEIN,TMTOP,VFCH(16,2),VCKM(3,3),VGCUT,VQCUT,
+     & VPCUT,ZBINM,EFFMIN,OMHMIX,ET2MIX,PH3MIX,GCUTME,
+     & IOPREM,IPRINT,ISPAC,LRSUD,LWSUD,MODPDF(2),NBTRY,NCOLO,NCTRY,
+     & NDTRY,NETRY,NFLAV,NGSPL,NSTRU,NSTRY,NZBIN,IOP4JT(2),NPRFMT,
+     & AZSOFT,AZSPIN,CLDIR(2),HARDME,NOSPAC,PRNDEC,PRVTX,SOFTME,ZPRIME,
+     & PRNDEF,PRNTEX,PRNWEB
+C
+      COMMON/HWPRCH/AUTPDF(2),BDECAY
+C
+C Parton shower common (same format as /HEPEVT/)
+      PARAMETER (NMXPAR=500)
+      COMMON/HWPART/NEVPAR,NPAR,ISTPAR(NMXPAR),IDPAR(NMXPAR),
+     & JMOPAR(2,NMXPAR),JDAPAR(2,NMXPAR),PPAR(5,NMXPAR),VPAR(4,NMXPAR)
+C
+C Parton polarization common
+      COMMON/HWPARP/DECPAR(2,NMXPAR),PHIPAR(2,NMXPAR),RHOPAR(2,NMXPAR),
+     & TMPAR(NMXPAR)
+C
+C Electroweak boson common
+      PARAMETER (MODMAX=5)
+      COMMON/HWBOSC/ALPFAC,BRHIG(12),ENHANC(12),GAMMAX,RHOHEP(3,NMXHEP),
+     & IOPHIG,MODBOS(MODMAX)
+C
+C Parton colour common
+      COMMON/HWPARC/JCOPAR(4,NMXPAR)
+C
+C other HERWIG branching, event and hard subprocess common blocks
+      COMMON/HWBRCH/ANOMSC(2,2),HARDST,PTINT(3,2),XFACT,INHAD,JNHAD,
+     & NSPAC(7),ISLENT,BREIT,FROST,USECMF
+C
+      COMMON/HWEVNT/AVWGT,EVWGT,GAMWT,TLOUT,WBIGST,WGTMAX,WGTSUM,WSQSUM,
+     & IDHW(NMXHEP),IERROR,ISTAT,LWEVT,MAXER,MAXPR,NOWGT,NRN(2),NUMER,
+     & NUMERU,NWGTS,GENSOF
+C
+      COMMON/HWHARD/ASFIXD,CLQ(7,6),COSS,COSTH,CTMAX,DISF(13,2),EMLST,
+     & EMMAX,EMMIN,EMPOW,EMSCA,EPOLN(3),GCOEF(7),GPOLN,OMEGA0,PHOMAS,
+     & PPOLN(3),PTMAX,PTMIN,PTPOW,Q2MAX,Q2MIN,Q2POW,Q2WWMN,Q2WWMX,QLIM,
+     & SINS,THMAX,Y4JT,TMNISR,TQWT,XX(2),XLMIN,XXMIN,YBMAX,YBMIN,YJMAX,
+     & YJMIN,YWWMAX,YWWMIN,WHMIN,ZJMAX,ZMXISR,IAPHIG,IBRN(2),IBSH,
+     & ICO(10),IDCMF,IDN(10),IFLMAX,IFLMIN,IHPRO,IPRO,MAPQ(6),MAXFL,
+     & BGSHAT,COLISR,FSTEVT,FSTWGT,GENEV,HVFCEN,TPOL,DURHAM
+C
+C Arrays for particle properties (NMXRES = max no of particles defined)
+      PARAMETER(NMXRES=500)
+      COMMON/HWPROP/RLTIM(0:NMXRES),RMASS(0:NMXRES),RSPIN(0:NMXRES),
+     & ICHRG(0:NMXRES),IDPDG(0:NMXRES),IFLAV(0:NMXRES),NRES,
+     & VTOCDK(0:NMXRES),VTORDK(0:NMXRES),
+     & QORQQB(0:NMXRES),QBORQQ(0:NMXRES)
+C
+      COMMON/HWUNAM/RNAME(0:NMXRES),TXNAME(2,0:NMXRES)
+C
+C Arrays for particle decays (NMXDKS = max total no of decays,
+C                             NMXMOD = max no of modes for a particle)
+      PARAMETER(NMXDKS=4000,NMXMOD=200)
+      COMMON/HWUPDT/BRFRAC(NMXDKS),CMMOM(NMXDKS),DKLTM(NMXRES),
+     & IDK(NMXDKS),IDKPRD(5,NMXDKS),LNEXT(NMXDKS),LSTRT(NMXRES),NDKYS,
+     & NME(NMXDKS),NMODES(NMXRES),NPRODS(NMXDKS),DKPSET,RSTAB(0:NMXRES)
+C
+C Weights used in cluster decays
+      COMMON/HWUWTS/REPWT(0:3,0:4,0:4),SNGWT,DECWT,QWT(3),PWT(12),
+     & SWTEF(NMXRES)
+C
+C Parameters for cluster decays (NMXCDK = max total no of cluster
+C                                         decay channels)
+      PARAMETER(NMXCDK=4000)
+      COMMON/HWUCLU/CLDKWT(NMXCDK),CTHRPW(12,12),PRECO,RESN(12,12),
+     & RMIN(12,12),LOCN(12,12),NCLDK(NMXCDK),NRECO,CLRECO
+C
+C Variables controling mixing and vertex information
+      COMMON/HWDIST/EXAG,GEV2MM,HBAR,PLTCUT,VMIN2,VTXPIP(4),XMIX(2),
+     & XMRCT(2),YMIX(2),YMRCT(2),IOPDKL,MAXDKL,MIXING,PIPSMR
+C
+C Arrays for temporarily storing heavy-b,c-hadrons decaying partonicaly
+C (NMXQDK = max no such decays in an event)
+      PARAMETER (NMXQDK=20)
+      COMMON/HWQDKS/VTXQDK(4,NMXQDK),IMQDK(NMXQDK),LOCQ(NMXQDK),NQDK
+C
+C Parameters for Sudakov form factors
+C (NMXSUD= max no of entries in lookup table)
+      PARAMETER (NMXSUD=1024)
+      COMMON/HWUSUD/ACCUR,QEV(NMXSUD,6),SUD(NMXSUD,6),INTER,NQEV,NSUD,
+     & SUDORD
+C
+      PARAMETER (NMXJET=200)
+C
+C SUSY parameters
+      COMMON/HWSUSY/
+     & TANB,ALPHAH,COSBPA,SINBPA,COSBMA,SINBMA,COSA,SINA,COSB,SINB,COTB,
+     & ZMIXSS(4,4),ZMXNSS(4,4),ZSGNSS(4), LFCH(16),RFCH(16),
+     & SLFCH(16,4),SRFCH(16,4), WMXUSS(2,2),WMXVSS(2,2), WSGNSS(2),
+     & QMIXSS(6,2,2),LMIXSS(6,2,2),
+     & THETAT,THETAB,THETAL,ATSS,ABSS,ALSS,MUSS,FACTSS,
+     & GHWWSS(3),GHZZSS(3),GHDDSS(4),GHUUSS(4),GHWHSS(3),
+     & GHSQSS(4,6,2,2),XLMNSS,RMMNSS,IMSSM,SENHNC(24),SSPARITY,SUSYIN
+C
+C R-Parity violating parameters and colours
+      COMMON /HWRPAR/ LAMDA1(3,3,3),LAMDA2(3,3,3),
+     &                LAMDA3(3,3,3),HRDCOL(2,5),RPARTY,COLUPD
+C
+C Parameters for minimum bias/soft underlying event
+      COMMON/HWMINB/
+     & PMBN1,PMBN2,PMBN3,PMBK1,PMBK2,PMBM1,PMBM2,PMBP1,PMBP2,PMBP3
+C
+C Cluster common used by soft event routines
+      PARAMETER (NMXCL=500)
+      COMMON/HWCLUS/PPCL(5,NMXCL),IDCL(NMXCL),NCL
diff --git a/HERWIG/HERWIG6100.f b/HERWIG/HERWIG6100.f
new file mode 100644 (file)
index 0000000..cdcd805
--- /dev/null
@@ -0,0 +1,31811 @@
+C-----------------------------------------------------------------------
+C                           H E R W I G
+C
+C            a Monte Carlo event generator for simulating
+C        +---------------------------------------------------+
+C        | Hadron Emission Reactions With Interfering Gluons |
+C        +---------------------------------------------------+
+C I.G. Knowles(*), G. Marchesini(+), M.H. Seymour($) and B.R. Webber(#)
+C-----------------------------------------------------------------------
+C with Minimal Supersymmetric Standard Model Matrix Elements by
+C                  S. Moretti($) and K. Odagiri($)
+C-----------------------------------------------------------------------
+C R parity violating Supersymmetric Decays and Matrix Elements by
+C                          P. Richardson(&)
+C-----------------------------------------------------------------------
+C matrix element corrections to top decay and Drell-Yan type processes
+C                         by G. Corcella(+)
+C-----------------------------------------------------------------------
+C Deep Inelastic Scattering and Heavy Flavour Electroproduction by
+C                  G. Abbiendi(@) and L. Stanco(%)
+C-----------------------------------------------------------------------
+C and Jet Photoproduction in Lepton-Hadron Collisions by J. Chyla(~)
+C-----------------------------------------------------------------------
+C(*)  Department of Physics & Astronomy, University of Edinburgh
+C(+)  Dipartimento di Fisica, Universita di Milano
+C($)  Rutherford Appleton Laboratory
+C(#)  Cavendish Laboratory, Cambridge
+C(&)  Department of Physics, University of Oxford
+C(@)  Dipartimento di Fisica, Universita di Bologna
+C(%)  Dipartimento di Fisica, Universita di Padova
+C(~)  Institute of Physics, Prague
+C-----------------------------------------------------------------------
+C                  Version 6.100 - 16th December 1999
+C-----------------------------------------------------------------------
+C Main reference:
+C    G.Marchesini,  B.R.Webber,  G.Abbiendi,  I.G.Knowles,  M.H.Seymour,
+C    and L.Stanco, Computer Physics Communications 67 (1992) 465.
+C-----------------------------------------------------------------------
+C Please send e-mail about  this program  to one of the  authors at the
+C following Internet addresses:
+C    I.Knowles@ed.ac.uk        Giuseppe.Marchesini@mi.infn.it
+C    M.Seymour@rl.ac.uk        webber@hep.phy.cam.ac.uk
+C-----------------------------------------------------------------------
+CDECK  ID>, DECADD.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Luca Stanco
+C-----------------------------------------------------------------------
+      SUBROUTINE DECADD(LOGI)
+C-----------------------------------------------------------------------
+C     DUMMY SUBROUTINE: DELETE AND SET BDECAY='CLEO'
+C     IN MAIN PROGRAM IF YOU USE CLEO DECAY PACKAGE
+C-----------------------------------------------------------------------
+      LOGICAL LOGI
+      WRITE (6,10)
+   10 FORMAT(/10X,'DECADD CALLED BUT NOT LINKED')
+      STOP
+      END
+CDECK  ID>, EUDINI.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Luca Stanco
+C-----------------------------------------------------------------------
+      SUBROUTINE EUDINI
+C-----------------------------------------------------------------------
+C     DUMMY SUBROUTINE: DELETE AND SET BDECAY='EURO'
+C     IN MAIN PROGRAM IF YOU USE EURODEC DECAY PACKAGE
+C-----------------------------------------------------------------------
+      WRITE (6,10)
+   10 FORMAT(/10X,'EUDINI CALLED BUT NOT LINKED')
+      STOP
+      END
+CDECK  ID>, FRAGMT.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Luca Stanco
+C-----------------------------------------------------------------------
+      SUBROUTINE FRAGMT(I,J,K)
+C-----------------------------------------------------------------------
+C     DUMMY SUBROUTINE: DELETE AND SET BDECAY='EURO'
+C     IN MAIN PROGRAM IF YOU USE EURODEC DECAY PACKAGE
+C-----------------------------------------------------------------------
+      INTEGER I,J,K
+      WRITE (6,10)
+   10 FORMAT(/10X,'FRAGMT CALLED BUT NOT LINKED')
+      STOP
+      END
+CDECK  ID>, HVCBVI.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HVCBVI
+C-----------------------------------------------------------------------
+C     DUMMY ROUTINE: DELETE IF YOU LINK TO BARYON NUMBER VIOLATN PACKAGE
+C-----------------------------------------------------------------------
+      WRITE (6,10)
+   10 FORMAT(/10X,'HVCBVI CALLED BUT NOT LINKED')
+      STOP
+      END
+CDECK  ID>, HVHBVI.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HVHBVI
+C-----------------------------------------------------------------------
+C     DUMMY ROUTINE: DELETE IF YOU LINK TO BARYON NUMBER VIOLATN PACKAGE
+C-----------------------------------------------------------------------
+      WRITE (6,10)
+   10 FORMAT(/10X,'HERBVI CALLED BUT NOT LINKED')
+      STOP
+      END
+CDECK  ID>, HWBAZF.
+*CMZ :-        -26/04/91  11.11.54  by  Bryan Webber
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBAZF(IPAR,JPAR,VEC1,VEC2,VEC3,VEC)
+C-----------------------------------------------------------------------
+C     Azimuthal correlation functions for Collins' algorithm,
+C     see I.G.Knowles, Comp. Phys. Comm. 58 (90) 271 for notation.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION Z1,Z2,DOT12,DOT23,DOT31,TR,FN(7),VEC1(2),VEC2(2),
+     & VEC3(2),VEC(2)
+      INTEGER IPAR,JPAR
+      LOGICAL GLUI,GLUJ
+      IF (.NOT.AZSPIN) RETURN
+      Z1=PPAR(4,JPAR)/PPAR(4,IPAR)
+      Z2=1.-Z1
+      GLUI=IDPAR(IPAR).EQ.13
+      GLUJ=IDPAR(JPAR).EQ.13
+      IF (GLUI) THEN
+         IF (GLUJ) THEN
+C           Branching: g--->gg
+            FN(2)=Z2/Z1
+            FN(3)=1./FN(2)
+            FN(4)=Z1*Z2
+            FN(1)=FN(2)+FN(3)+FN(4)
+            FN(5)=FN(2)+2.*Z1
+            FN(6)=FN(3)+2.*Z2
+            FN(7)=FN(4)-2.
+         ELSE
+C           Branching: g--->qqbar
+            FN(1)=(Z1*Z1+Z2*Z2)/2.
+            FN(2)=0.
+            FN(3)=0.
+            FN(4)=-Z1*Z2
+            FN(5)=-(2.*Z1-1.)/2.
+            FN(6)=-FN(5)
+            FN(7)=FN(1)
+         ENDIF
+      ELSE
+         IF (GLUJ) THEN
+C           Branching: q--->gq
+            FN(1)=(1.+Z2*Z2)/(2.*Z1)
+            FN(2)=Z2/Z1
+            FN(3)=0.
+            FN(4)=0.
+            FN(5)=FN(1)
+            FN(6)=(1.+Z2)/2.
+            FN(7)=-FN(6)
+         ELSE
+C           Branching: q--->qg
+            FN(1)=(1.+Z1*Z1)/(2.*Z2)
+            FN(2)=0.
+            FN(3)=Z1/Z2
+            FN(4)=0.
+            FN(5)=(1.+Z1)/2.
+            FN(6)=FN(1)
+            FN(7)=-FN(5)
+         ENDIF
+      ENDIF
+      DOT12=VEC1(1)*VEC2(1)+VEC1(2)*VEC2(2)
+      DOT23=VEC2(1)*VEC3(1)+VEC2(2)*VEC3(2)
+      DOT31=VEC3(1)*VEC1(1)+VEC3(2)*VEC1(2)
+      TR=1./(FN(1)+FN(2)*DOT23+FN(3)*DOT31+FN(4)*DOT12)
+      VEC(1)=((FN(2)+FN(5)*DOT23)*VEC1(1)
+     &       +(FN(3)+FN(6)*DOT31)*VEC2(1)
+     &       +(FN(4)+FN(7)*DOT12)*VEC3(1))*TR
+      VEC(2)=((FN(2)+FN(5)*DOT23)*VEC1(2)
+     &       +(FN(3)+FN(6)*DOT31)*VEC2(2)
+     &       +(FN(4)+FN(7)*DOT12)*VEC3(2))*TR
+      END
+CDECK  ID>, HWBCON.
+*CMZ :-        -26/04/91  10.18.56  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBCON
+C-----------------------------------------------------------------------
+C     MAKES COLOUR CONNECTIONS BETWEEN JETS
+C     MODIFIED 12/10/97 BY BRW FOR SUSY PROCESSES
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,IST,ID,JC,KC,JD,JHEP,LHEP,ID2
+      IF (IERROR.NE.0) RETURN
+      IF(.NOT.RPARTY) THEN
+        CALL HWBRCN
+        RETURN
+      ENDIF
+      DO 20 IHEP=1,NHEP
+      IST=ISTHEP(IHEP)
+C---LOOK FOR PARTONS WITHOUT COLOUR MOTHERS
+      IF (IST.LT.145.OR.IST.GT.152) GOTO 20
+      IF (JMOHEP(2,IHEP).EQ.0) THEN
+C---FIND COLOUR-CONNECTED PARTON
+        JC=JMOHEP(1,IHEP)
+        IF (IST.NE.152) JC=JMOHEP(1,JC)
+        JC =JMOHEP(2,JC)
+        IF (JC.EQ.0) CALL HWWARN('HWBCON',51,*20)
+C---FIND SPECTATOR WHEN JC IS DECAYED HEAVY QUARK OR SUSY PARTICLE
+        IF (ISTHEP(JC).EQ.155) THEN
+          IF (IDHEP(JMOHEP(1,JC)).EQ.94) THEN
+C---DECAYED BEFORE HADRONIZING
+            JHEP=JMOHEP(2,JC)
+            IF (JHEP.EQ.0) GO TO 20
+            ID=IDHW(JHEP)
+            IF (ISTHEP(JHEP).EQ.155) THEN
+C---SPECIAL FOR GLUINO DECAYS
+              IF (ID.EQ.449) THEN
+                ID=IDHW(JC)
+C---N.B. WILL NEED MODS WHEN SUSY PARTICLES CAN SHOWER
+                IF (ID.EQ.449.OR.ID.EQ.13.OR.
+     &             (ID.GE.401.AND.ID.LE.406).OR.
+     &             (ID.GE.413.AND.ID.LE.418).OR.
+     &             ID.LE.6.OR.(ID.GE.115.AND.ID.LE.120)) THEN
+C---LOOK FOR ANTI(S)QUARK OR GLUON
+                  DO KC=JDAHEP(1,JHEP),JDAHEP(2,JHEP)
+                    ID=IDHW(KC)
+                    IF ((ID.GE.  7.AND.ID.LE. 13).OR.
+     &                  (ID.GE.407.AND.ID.LE.412).OR.
+     &                  (ID.GE.419.AND.ID.LE.424)) GOTO 5
+                  ENDDO
+                ELSE
+C---LOOK FOR (S)QUARK OR GLUON
+                  DO KC=JDAHEP(1,JHEP),JDAHEP(2,JHEP)
+                    ID=IDHW(KC)
+                    IF (ID.LE.  6.OR. ID.EQ. 13.OR.
+     &                 (ID.GE.401.AND.ID.LE.406).OR.
+     &                 (ID.GE.413.AND.ID.LE.418)) GOTO 5
+                  ENDDO
+                ENDIF
+C---COULDNT FIND ONE
+                CALL HWWARN('HWBCON',101,*999)
+    5           JC=KC
+              ELSE
+C--PR MOD 30/6/99 should fix HWCFOR 104 errors
+                ID2 = IDHW(IHEP)
+                IF(IDHW(JDAHEP(1,JHEP)).EQ.449.AND.
+     &             (ID2.LE.6.OR.(ID2.GE.115.AND.ID2.LE.120).OR.
+     &             (ID2.GE.401.AND.ID2.LE.406).OR.ID2.EQ.13.OR.
+     &             (ID2.GE.413.AND.ID2.LE.418).OR.ID2.EQ.449)) THEN
+                  JC = JDAHEP(1,JHEP)
+                ELSE
+                  JC=JDAHEP(2,JHEP)
+                ENDIF
+              ENDIF
+            ELSEIF (ID.EQ.6.OR.ID.EQ.12.OR.
+     &      (ID.GE.209.AND.ID.LE.218).OR.
+     &      (ID.GE.401.AND.ID.LE.424).OR.ID.EQ.449) THEN
+C Wait for partner heavy quark to decay
+C              RETURN
+C---N.B. MAY BE A PROBLEM HERE
+              GOTO 20
+            ELSE
+              JMOHEP(2,IHEP)=JHEP
+              JDAHEP(2,JHEP)=IHEP
+              GOTO 20
+            ENDIF
+          ELSE
+            JC=JMOHEP(2,JC)
+          ENDIF
+        ENDIF
+        JC=JDAHEP(1,JC)
+        JD=JDAHEP(2,JC)
+C---SEARCH IN CORRESPONDING JET
+        IF (JD.LT.JC) JD=JC
+        LHEP=0
+        DO 10 JHEP=JC,JD
+        IF (ISTHEP(JHEP).LT.145.OR.ISTHEP(JHEP).GT.152) GOTO 10
+        IF (JDAHEP(2,JHEP).EQ.IHEP) LHEP=JHEP
+        IF (JDAHEP(2,JHEP).NE.0) GOTO 10
+C---JOIN IHEP AND JHEP
+        JMOHEP(2,IHEP)=JHEP
+        JDAHEP(2,JHEP)=IHEP
+        GOTO 20
+   10   CONTINUE
+        IF (LHEP.NE.0) THEN
+          JMOHEP(2,IHEP)=LHEP
+C        ELSE
+C---DIDN'T FIND PARTNER OF IHEP YET
+C          CALL HWWARN('HWBCON',52,*20)
+        ENDIF
+      ENDIF
+  20  CONTINUE
+C---BREAK COLOUR CONNECTIONS WITH PHOTONS
+      IHEP=1
+  30  IF (IHEP.LE.NHEP) THEN
+        IF (IDHW(IHEP).EQ.59 .AND. ISTHEP(IHEP).EQ.149) THEN
+C  BRW FIX 13/03/99
+          IF (JMOHEP(2,IHEP).NE.0) THEN
+            IF (JDAHEP(2,JMOHEP(2,IHEP)).EQ.IHEP)
+     &        JDAHEP(2,JMOHEP(2,IHEP))=JDAHEP(2,IHEP)
+          ENDIF
+C  END FIX
+          IF (JDAHEP(2,IHEP).NE.0) THEN
+            IF (JMOHEP(2,JDAHEP(2,IHEP)).EQ.IHEP)
+     &        JMOHEP(2,JDAHEP(2,IHEP))=JMOHEP(2,IHEP)
+          ENDIF
+          JMOHEP(2,IHEP)=IHEP
+          JDAHEP(2,IHEP)=IHEP
+        ENDIF
+        IHEP=IHEP+1
+        GOTO 30
+      ENDIF
+  999 END
+CDECK  ID>, HWBDED.
+*CMZ :-        -22/04/96  13.54.08  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBDED(IOPT)
+C     FILL MISSING AREA OF DALITZ PLOT WITH 3-JET AND 2-JET+GAMMA EVENTS
+C     IF (IOPT.EQ.1) SET UP EVENT RECORD
+C     IF (IOPT.EQ.2) CLEAN UP EVENT RECORD AFTER SHOWERING
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBVMC,HWR,HWUALF,HWUSQR,X(3),W,WMAX,WSUM,
+     & X1MIN,X1MAX,X2MIN,X2MAX,QSCALE,GAMFAC,GLUFAC,R(3,3),CS,SN,M(3),
+     & E(3),LAMBDA,A,B,C,PTSQ,EM,P1(5),P2(5),PVRT(4),EPS,MASDEP
+      INTEGER ID,ID3,EMIT,NOEMIT,IEVT,IHEP,JHEP,KHEP,ICMF,IOPT,IEDT(3),
+     & I,NDEL
+      EXTERNAL HWBVMC,HWR,HWUALF,HWUSQR
+      SAVE X,WMAX
+      DATA WSUM,WMAX,X1MIN,X1MAX,EMIT,ICMF,IEVT
+     & /0.994651,1.84096,0,0.773459,3*0/
+      LAMBDA(A,B,C)=(A**2+B**2+C**2-2*A*B-2*B*C-2*C*A)/(4*A)
+      IF (IOPT.EQ.1) THEN
+C---FIND AN UNTREATED CMF
+        IF (IEVT.EQ.NEVHEP+NWGTS) RETURN
+        IEVT=0
+        ICMF=0
+        DO 10 IHEP=1,NHEP
+ 10       IF (ICMF.EQ.0 .AND. ISTHEP(IHEP).EQ.110 .AND.
+     &    JDAHEP(2,IHEP).EQ.JDAHEP(1,IHEP)+1) ICMF=IHEP
+        IF (ICMF.EQ.0) RETURN
+        EM=PHEP(5,ICMF)
+        IF (EM.LT.2*HWBVMC(1)) RETURN
+C---GENERATE X1,X2 ACCORDING TO 1/((1-X1)*(1-X2))
+ 100    CONTINUE
+C---CHOOSE X1
+        X(1)=1-(1-X1MAX)*((1-X1MIN)/(1-X1MAX))**HWR()
+C---CHOOSE X2
+        X2MIN=MAX(X(1),1-X(1))
+        X2MAX=(4*X(1)-3+2*REAL(  CMPLX(  X(1)**3+135*(X(1)-1)**3,
+     &    3*HWUSQR(3*(128*X(1)**4-368*X(1)**3+405*X(1)**2-216*X(1)+54))*
+     &    (X(1)-1)  )**(1./3)  ))/3
+        IF (X2MAX.GE.ONE.OR.X2MIN.GE.ONE.OR.X2MAX.LE.X2MIN) GOTO 100
+        X(2)=1-(1-X2MAX)*((1-X2MIN)/(1-X2MAX))**HWR()
+C---CALCULATE WEIGHT
+        W=2 * LOG((1-X1MIN)/(1-X1MAX))*LOG((1-X2MIN)/(1-X2MAX)) *
+     &    (X(1)**2+X(2)**2)
+C---GENERATE UNWEIGHTED (X1,X2) PAIRS (EFFICIENCY IS ~50%)
+        IF (WMAX*HWR().GT.W) GOTO 100
+C---SYMMETRIZE X1,X2
+        X(3)=2-X(1)-X(2)
+        IF (HWR().GT.HALF) THEN
+          X(1)=X(2)
+          X(2)=2-X(3)-X(1)
+        ENDIF
+C---CHOOSE WHICH PARTON WILL EMIT
+        EMIT=1
+        IF (HWR().LT.X(1)**2/(X(1)**2+X(2)**2)) EMIT=2
+        NOEMIT=3-EMIT
+        IHEP=JDAHEP(  EMIT,ICMF)
+        JHEP=JDAHEP(NOEMIT,ICMF)
+C---PREFACTORS FOR GAMMA AND GLUON CASES
+        QSCALE=HWUSQR((1-X(1))*(1-X(2))*(1-X(3)))*EM/X(NOEMIT)
+        ID=IDHW(JDAHEP(1,ICMF))
+        GAMFAC=ALPFAC*ALPHEM*ICHRG(ID)**2/(18*PIFAC)
+        GLUFAC=0
+        IF (QSCALE.GT.HWBVMC(13))
+     &    GLUFAC=CFFAC/(2*PIFAC)*HWUALF(1,QSCALE)
+C---IN FRACTION FAC*WSUM OF EVENTS ADD A GAMMA/GLUON
+        IF     (GAMFAC*WSUM .GT. HWR()) THEN
+          ID3=59
+        ELSEIF (GLUFAC*WSUM .GT. HWR()) THEN
+          ID3=13
+        ELSE
+          EMIT=0
+          RETURN
+        ENDIF
+C---CHECK INFRA-RED CUT-OFF FOR GAMMA/GLUON
+        M(1)=HWBVMC(ID)
+        M(2)=HWBVMC(ID)
+        M(3)=HWBVMC(ID3)
+        E(1)=HALF*EM*(X(1)+(M(1)**2-M(2)**2-M(3)**2)/EM**2)
+        E(2)=HALF*EM*(X(2)+(M(2)**2-M(3)**2-M(1)**2)/EM**2)
+        E(3)=EM-E(1)-E(2)
+        PTSQ=-LAMBDA(E(NOEMIT)**2-M(NOEMIT)**2,E(3)**2-M(3)**2,
+     &    E(EMIT)**2-M(EMIT)**2)
+        IF (PTSQ.LE.ZERO .OR.
+     $       E(1).LE.M(1).OR.E(2).LE.M(2).OR.E(3).LE.M(3)) THEN
+          EMIT=0
+          RETURN
+        ENDIF
+C---CALCULATE MASS-DEPENDENT SUPRESSION
+        IF (MOD(IPROC,10).GT.0) THEN
+          EPS=(RMASS(ID)/EM)**2
+          MASDEP=X(1)**2+X(2)**2
+     $         -4*EPS*X(3)-2*EPS*((1-X(2))/(1-X(1))+(1-X(1))/(1-X(2)))
+     $         -4*EPS**2*X(3)**2/((1-X(1))*(1-X(2)))
+          IF (MASDEP.LT.HWR()*(X(1)**2+X(2)**2)) THEN
+            EMIT=0
+            RETURN
+          ENDIF
+        ENDIF
+C---STORE OLD MOMENTA
+        CALL HWVEQU(5,PHEP(1,JDAHEP(1,ICMF)),P1)
+        CALL HWVEQU(5,PHEP(1,JDAHEP(2,ICMF)),P2)
+C---GET THE NON-EMITTING PARTON'S CMF DIRECTION
+        CALL HWULOF(PHEP(1,ICMF),PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWRAZM(ONE,CS,SN)
+        CALL HWUROT(PHEP(1,JHEP),CS,SN,R)
+        M(1)=PHEP(5,IHEP)
+        M(2)=PHEP(5,JHEP)
+        M(3)=RMASS(ID3)
+C---REORDER ENTRIES: IHEP=EMITTER, JHEP=NON-EMITTER, KHEP=EMITTED
+        NHEP=NHEP+1
+        IF (IDHW(IHEP).LT.IDHW(JHEP)) THEN
+          IHEP=JDAHEP(1,ICMF)
+          JHEP=NHEP
+        ELSE
+          IHEP=NHEP
+          JHEP=JDAHEP(1,ICMF)
+        ENDIF
+        KHEP=JDAHEP(2,ICMF)
+C---SET UP MOMENTA
+        PHEP(5,JHEP)=M(NOEMIT)
+        PHEP(5,IHEP)=M(EMIT)
+        PHEP(5,KHEP)=M(3)
+        PHEP(4,JHEP)=HALF*EM*(X(NOEMIT)+
+     &                  (M(NOEMIT)**2-M(EMIT)**2-M(3)**2)/EM**2)
+        PHEP(4,IHEP)=HALF*EM*(X(EMIT)+
+     &                  (M(EMIT)**2-M(NOEMIT)**2-M(3)**2)/EM**2)
+        PHEP(4,KHEP)=EM-PHEP(4,IHEP)-PHEP(4,JHEP)
+        PHEP(3,JHEP)=HWUSQR(PHEP(4,JHEP)**2-PHEP(5,JHEP)**2)
+        PHEP(3,IHEP)=( (PHEP(4,KHEP)**2-PHEP(5,KHEP)**2) -
+     &    (PHEP(4,IHEP)**2-PHEP(5,IHEP)**2) -
+     &    (PHEP(3,JHEP)**2) )*HALF/PHEP(3,JHEP)
+        PHEP(3,KHEP)=-PHEP(3,IHEP)-PHEP(3,JHEP)
+        PHEP(2,JHEP)=0
+        PHEP(2,IHEP)=0
+        PHEP(2,KHEP)=0
+        PHEP(1,JHEP)=0
+        PHEP(1,IHEP)=HWUSQR(PHEP(4,IHEP)**2-
+     &    PHEP(3,IHEP)**2-PHEP(5,IHEP)**2)
+        PHEP(1,KHEP)=-PHEP(1,IHEP)
+C---ORIENT IN CMF, THEN BOOST TO LAB
+        CALL HWUROB(R,PHEP(1,IHEP),PHEP(1,IHEP))
+        CALL HWUROB(R,PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWUROB(R,PHEP(1,KHEP),PHEP(1,KHEP))
+        CALL HWULOB(PHEP(1,ICMF),PHEP(1,IHEP),PHEP(1,IHEP))
+        CALL HWULOB(PHEP(1,ICMF),PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWULOB(PHEP(1,ICMF),PHEP(1,KHEP),PHEP(1,KHEP))
+C---CALCULATE PRODUCTION VERTICES
+        CALL HWVZRO(4,VHEP(1,JHEP))
+        CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,KHEP),PVRT)
+        CALL HWUDKL(ID,PVRT,VHEP(1,KHEP))
+        CALL HWVEQU(4,VHEP(1,KHEP),VHEP(1,IHEP))
+C---REORDER ENTRIES: IHEP=QUARK, JHEP=ANTI-QUARK, KHEP=EMITTED
+        IF (IHEP.EQ.NHEP) THEN
+          IHEP=JHEP
+          JHEP=NHEP
+        ENDIF
+C---STATUS, ID AND POINTERS
+        ISTHEP(JHEP)=114
+        IDHW(JHEP)=IDHW(KHEP)
+        IDHEP(JHEP)=IDHEP(KHEP)
+        IDHW(KHEP)=ID3
+        IDHEP(KHEP)=IDPDG(ID3)
+        JDAHEP(2,ICMF)=JHEP
+        JMOHEP(1,JHEP)=ICMF
+        JDAHEP(1,JHEP)=0
+C---COLOUR CONNECTIONS AND GLUON POLARIZATION
+        JMOHEP(2,JHEP)=IHEP
+        JDAHEP(2,IHEP)=JHEP
+        IF (ID3.EQ.13) THEN
+          JMOHEP(2,IHEP)=KHEP
+          JMOHEP(2,KHEP)=JHEP
+          JDAHEP(2,JHEP)=KHEP
+          JDAHEP(2,KHEP)=IHEP
+          GPOLN=((1-X(1))**2+(1-X(2))**2)/(4*(1-X(3)))
+          GPOLN=1/(1+GPOLN)
+        ELSE
+          JMOHEP(2,IHEP)=JHEP
+          JMOHEP(2,KHEP)=KHEP
+          JDAHEP(2,JHEP)=IHEP
+          JDAHEP(2,KHEP)=KHEP
+        ENDIF
+        IEVT=NEVHEP+NWGTS
+      ELSEIF (IOPT.EQ.2) THEN
+C---MAKE THREE-JET EVENTS FROM THE `DEAD-ZONE' LOOK LIKE TWO-JET EVENTS
+        IF (EMIT.EQ.0.OR.IEVT.NE.NEVHEP+NWGTS) THEN
+          RETURN
+        ELSEIF (EMIT.EQ.1) THEN
+          IHEP=JDAHEP(1,JDAHEP(1,ICMF)+1)
+          JHEP=JDAHEP(1,JDAHEP(1,ICMF))
+        ELSE
+          IHEP=JDAHEP(1,JDAHEP(2,ICMF))
+          JHEP=JDAHEP(1,JDAHEP(1,ICMF)+1)
+          JDAHEP(1,JDAHEP(2,ICMF))=JHEP
+          IDHW(JHEP)=IDHW(IHEP)
+          IF (ISTHEP(IHEP+1).EQ.100 .AND. ISTHEP(JHEP+1).EQ.100)
+     &      CALL HWVEQU(5,PHEP(1,IHEP+1),PHEP(1,JHEP+1))
+        ENDIF
+        JMOHEP(2,JDAHEP(1,ICMF))=JDAHEP(2,ICMF)
+        JDAHEP(2,JDAHEP(1,ICMF))=JDAHEP(2,ICMF)
+        JMOHEP(2,JDAHEP(2,ICMF))=JDAHEP(1,ICMF)
+        JDAHEP(2,JDAHEP(2,ICMF))=JDAHEP(1,ICMF)
+        CALL HWVEQU(5,P1,PHEP(1,JDAHEP(1,ICMF)))
+        CALL HWVEQU(5,P2,PHEP(1,JDAHEP(2,ICMF)))
+        CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWUMAS(PHEP(1,JHEP))
+        JDAHEP(2,JHEP)=JDAHEP(2,IHEP)
+        IEDT(1)=JDAHEP(1,ICMF)+1
+        IEDT(2)=IHEP
+        IEDT(3)=IHEP+1
+        NDEL=3
+        IF (ISTHEP(IHEP+1).NE.100) NDEL=2
+        CALL HWUEDT(NDEL,IEDT)
+        DO 410 I=1,2
+          IHEP=JDAHEP(1,JDAHEP(I,ICMF))
+          JMOHEP(1,IHEP)=JDAHEP(I,ICMF)
+          IF (ISTHEP(IHEP+1).EQ.100) THEN
+            JMOHEP(1,IHEP+1)=JMOHEP(1,IHEP)
+            JMOHEP(2,IHEP+1)=JMOHEP(2,JMOHEP(1,IHEP))
+          ENDIF
+          DO 400 JHEP=JDAHEP(1,IHEP),JDAHEP(2,IHEP)
+            JMOHEP(1,JHEP)=IHEP
+ 400      CONTINUE
+          CALL HWVZRO(4,VHEP(1,JDAHEP(I,ICMF)))
+          CALL HWVZRO(4,VHEP(1,IHEP))
+          IF (ISTHEP(IHEP+1).EQ.100) CALL HWVZRO(4,VHEP(1,IHEP+1))
+ 410    CONTINUE
+        EMIT=0
+        IEVT=0
+      ELSE
+        CALL HWWARN('HWBDED',500,*999)
+      ENDIF
+ 999  END
+CDECK  ID>, HWBDIS.
+*CMZ :-        -17/05/94  09.33.08  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBDIS(IOPT)
+C-----------------------------------------------------------------------
+C     FILL MISSING AREA OF DIS PHASE-SPACE WITH 2+1-JET EVENTS
+C     IF (IOPT.EQ.1) SET UP EVENT RECORD
+C     IF (IOPT.EQ.2) CLEAN UP EVENT RECORD AFTER SHOWERING
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,HWBVMC,HWUALF,HWULDO,P1(5),P2(5),P3(5),
+     & PCMF(5),L(5),R(3,3),Q,XBJ,RN,XPMIN,XPMAX,XP,ZPMIN,ZPMAX,ZP,FAC,
+     & X1,X2,XTSQ,XT,PTSQ,SIN1,SIN2,W1,W2,CFAC,PDFOLD(13),PDFNEW(13),
+     & PHI,SCALE,Q1(5),Q2(5),DIR1,DIR2,DIR,PM(5),POLD,PNEW,COMINT,
+     & BGFINT,COMWGT,C1,C2,CM,B1,B2,BM,PVRT(4)
+      INTEGER IOPT,EMIT,ICMF,IHEP,JHEP,IIN,IOUT,ILEP,IHAD,ID,IDNEW,
+     & IEDT(3),NDEL,NTRY,ITEMP
+      LOGICAL BGF
+      EXTERNAL HWR,HWBVMC,HWUALF,HWULDO
+      SAVE BGF,IIN,IOUT,ICMF,ID,Q1,Q2,XP,XBJ
+      DATA EMIT,COMINT,BGFINT,COMWGT/0,3.9827,1.2462,0.3/
+      DATA C1,C2,CM,B1,B2,BM/0.56,0.20,10,0.667,0.167,3/
+      IF (IERROR.NE.0) RETURN
+      IF (IOPT.EQ.1) THEN
+C---FIND AN UNTREATED CMF
+        IF (EMIT.EQ.NEVHEP+NWGTS) RETURN
+        ICMF=0
+        DO 10 IHEP=1,NHEP
+ 10       IF (ICMF.EQ.0 .AND. ISTHEP(IHEP).EQ.110 .AND.
+     &    JDAHEP(2,IHEP).EQ.JDAHEP(1,IHEP)+1) ICMF=IHEP
+        IF (ICMF.EQ.0) RETURN
+        IIN=JMOHEP(2,ICMF)
+        IOUT=JDAHEP(2,ICMF)
+        ILEP=JMOHEP(1,ICMF)
+        CALL HWVEQU(5,PHEP(1,IIN),P1)
+        CALL HWVEQU(5,PHEP(1,IOUT),P2)
+        CALL HWVEQU(5,PHEP(1,ILEP),L)
+        IHAD=2
+        IF (JDAHEP(1,IHAD).NE.0) IHAD=JDAHEP(1,IHAD)
+        ID=IDHW(IIN)
+C---STORE OLD MOMENTA
+        CALL HWVEQU(5,P1,Q1)
+        CALL HWVEQU(5,P2,Q2)
+C---BOOST AND ROTATE THE MOMENTA TO THE BREIT FRAME
+        CALL HWVDIF(4,P2,P1,PCMF)
+        CALL HWUMAS(PCMF)
+        CALL HWVEQU(5,PHEP(1,IHAD),PM)
+        Q=-PCMF(5)
+        XBJ=HALF*Q**2/HWULDO(PM,PCMF)
+        CALL HWVSCA(4,HALF/XBJ,PCMF,PCMF)
+        CALL HWVSUM(4,PM,PCMF,PCMF)
+        CALL HWUMAS(PCMF)
+        CALL HWULOF(PCMF,L,L)
+        CALL HWULOF(PCMF,PM,PM)
+        CALL HWUROT(PM,ONE,ZERO,R)
+        CALL HWUROF(R,L,L)
+        PHI=ATAN2(L(2),L(1))
+        CALL HWUROT(PM,COS(PHI),SIN(PHI),R)
+C---CHOOSE THE HADRONIC-PLANE CONFIGURATION, XP,ZP
+        IF (HWR().LT.COMWGT) THEN
+C-----CONSIDER GENERATING A QCD COMPTON EVENT
+          BGF=.FALSE.
+          P3(5)=RMASS(13)
+ 100      RN=HWR()
+          IF (RN.LT.C1) THEN
+            ZP=HWR()
+            XPMAX=MIN(ZP,1-ZP)
+            XP=HWR()*XPMAX
+            FAC=1/C1*2*XPMAX/((1-XP)*(1-ZP))*
+     $           (1+(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+            IF (HWR().LT.HALF) THEN
+              ZPMAX=ZP
+              ZP=XP
+              XP=ZPMAX
+            ENDIF
+          ELSEIF (RN.LT.C1+C2) THEN
+            XPMAX=0.83
+            XP=XPMAX*HWR()
+            ZPMIN=MAX(XP,1-XP)
+            ZPMAX=1-2./3.*XP*(1+REAL( CMPLX(10-45*XP+18*XP**2,3*SQRT(
+     $         3*(9+66*XP-93*XP**2+12*XP**3-8*XP**4+24*XP**5-8*XP**6)))
+     $         **(1./3.) * CMPLX(0.5,0.8660254) ))
+            ZP=1-((1-ZPMIN)/(1-ZPMAX))**HWR()*(1-ZPMAX)
+            FAC=1/C2*XPMAX*LOG((1-ZPMIN)/(1-ZPMAX))/(1-XP)*
+     $           (1+(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+          ELSE
+            ZPMAX=0.85
+            ZP=ZPMAX*HWR()
+            XPMIN=MAX(ZP,1-ZP)
+            XPMAX=(1+4*ZP*(1-ZP))/(1+6*ZP*(1-ZP))
+            XP=1-((1-XPMIN)/(1-XPMAX))**HWR()*(1-XPMAX)
+            FAC=1/(1-C1-C2)*ZPMAX*LOG((1-XPMIN)/(1-XPMAX))/(1-ZP)*
+     $           (1+(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+          ENDIF
+          XPMAX=(1+4*ZP*(1-ZP))/(1+6*ZP*(1-ZP))
+          ZPMAX=1-2./3.*XP*(1+REAL( CMPLX(10-45*XP+18*XP**2,3*SQRT(
+     $         3*(9+66*XP-93*XP**2+12*XP**3-8*XP**4+24*XP**5-8*XP**6)))
+     $         **(1./3.) * CMPLX(0.5,0.8660254) ))
+          IF (XP.GT.XPMAX.OR.ZP.GT.ZPMAX.OR.CM*HWR().GT.FAC)
+     $         GOTO 100
+        ELSE
+C-----CONSIDER GENERATING A BGF EVENT
+          BGF=.TRUE.
+          P3(5)=P1(5)
+          P1(5)=RMASS(13)
+ 110      RN=HWR()
+          IF (RN.LT.B1) THEN
+            ZP=HWR()
+            XPMAX=MIN(ZP,1-ZP)
+            XP=HWR()*XPMAX
+            FAC=1/B1*2*XPMAX/(1-ZP)*
+     $           ((  XP+ZP-2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP
+     $           +(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+            IF (HWR().LT.HALF) XP=1-XP
+          ELSEIF (RN.LT.B1+B2) THEN
+            XPMAX=0.83
+            XP=XPMAX*HWR()
+            ZPMIN=MAX(XP,1-XP)
+            ZPMAX=1-2./3.*XP*(1+REAL( CMPLX(10-45*XP+18*XP**2,3*SQRT(
+     $         3*(9+66*XP-93*XP**2+12*XP**3-8*XP**4+24*XP**5-8*XP**6)))
+     $         **(1./3.) * CMPLX(0.5,0.8660254) ))
+            ZP=1-((1-ZPMIN)/(1-ZPMAX))**HWR()*(1-ZPMAX)
+            FAC=1/B2*XPMAX*LOG((1-ZPMIN)/(1-ZPMAX))*
+     $           ((  XP+ZP-2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP
+     $           +(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+          ELSE
+            XPMAX=0.83
+            XP=XPMAX*HWR()
+            ZPMAX=MIN(XP,1-XP)
+            ZPMIN=2./3.*XP*(1+REAL( CMPLX(10-45*XP+18*XP**2,3*SQRT(
+     $         3*(9+66*XP-93*XP**2+12*XP**3-8*XP**4+24*XP**5-8*XP**6)))
+     $         **(1./3.) * CMPLX(0.5,0.8660254) ))
+            ZP=(ZPMAX-ZPMIN)*HWR()+ZPMIN
+            FAC=1/(1-B1-B2)*XPMAX*(ZPMAX-ZPMIN)/(1-ZP)*
+     $           ((  XP+ZP-2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP
+     $           +(1-XP-ZP+2*XP*ZP)**2+2*(1-XP)*(1-ZP)*XP*ZP)
+          ENDIF
+          ZPMAX=1-2./3.*XP*(1+REAL( CMPLX(10-45*XP+18*XP**2,3*SQRT(
+     $         3*(9+66*XP-93*XP**2+12*XP**3-8*XP**4+24*XP**5-8*XP**6)))
+     $         **(1./3.) * CMPLX(0.5,0.8660254) ))
+          IF (ZP.GT.ZPMAX.OR.ZP.LT.ONE-ZPMAX.OR.BM*HWR().GT.FAC)
+     $         GOTO 110
+        ENDIF
+C---CALCULATE THE ADDITIONAL FACTORS IN THE WEIGHT
+        IF (BGF) THEN
+          IDNEW=13
+          CFAC=1./2
+          FAC=BGFINT/(1-COMWGT)
+        ELSE
+          IDNEW=ID
+          CFAC=4./3
+          FAC=COMINT/COMWGT
+        ENDIF
+        SCALE=Q*SQRT((1-XP)*(1-ZP)*ZP/XP+1)
+        ITEMP=ISTAT
+        ISTAT=7
+        CALL HWSFUN(XBJ,Q,IDHW(IHAD),NSTRU,PDFOLD,2)
+        ISTAT=ITEMP
+        IF (PDFOLD(ID).LE.ZERO) CALL HWWARN('HWBDIS',100,*999)
+        IF (XP.GT.XBJ) THEN
+          CALL HWSFUN(XBJ/XP,SCALE,IDHW(IHAD),NSTRU,PDFNEW,2)
+          FAC=CFAC/(2*PIFAC) * HWUALF(1,SCALE) * FAC *
+     $         PDFNEW(IDNEW)/PDFOLD(ID)
+        ELSE
+          FAC=0
+        ENDIF
+C---FOR PHOTON BEAMS, INCLUDE DIRECT PHOTON COUPLING
+        IF (IDHW(IHAD).EQ.59) THEN
+          ZPMIN=2./3.*XBJ*(1+REAL( CMPLX(10-45*XBJ+18*XBJ**2,3*SQRT(
+     $         3*(9+66*XBJ-93*XBJ**2+12*XBJ**3-8*XBJ**4+24*XBJ**5
+     $         -8*XBJ**6)))**(1./3.) * CMPLX(0.5,0.8660254) ))
+          ZPMAX=1-ZPMIN
+          DIR1=(XBJ**2+(1-XBJ)**2)*(LOG(ZPMAX/ZPMIN)-(ZPMAX-ZPMIN))
+          DIR2=4*XBJ*(1-XBJ)*(ZPMAX-ZPMIN)
+          DIR=QFCH(MOD(ID-1,6)+1)**2*ALPHEM/(2*PIFAC*PDFOLD(ID))*XBJ
+     $         *(DIR1+DIR2)
+        ELSE
+          DIR=0
+        ENDIF
+C---DECIDE WHETHER TO MAKE AN EVENT HERE
+        IF (HWR().GT.FAC+DIR) RETURN
+C---FOR DIRECT COUPLING, CHOOSE ZP VALUE
+        IF ((FAC+DIR)*HWR().GT.FAC) THEN
+          IF ((DIR1+DIR2)*HWR().LT.DIR1) THEN
+            NTRY=0
+ 120        NTRY=NTRY+2
+            ZP=1-(ZPMAX/ZPMIN)**HWR()*ZPMIN
+            IF ((ZPMIN**2+(1-ZPMIN)**2)*HWR().GT.ZP**2+(1-ZP)**2)
+     $           GOTO 120
+          ELSE
+            ZP=SQRT((ZPMAX-ZPMIN)*HWR()+ZPMIN**2)
+          ENDIF
+          XP=XBJ
+          BGF=.TRUE.
+          P3(5)=P2(5)
+          P1(5)=0
+        ENDIF
+        X1=1-   ZP /XP
+        X2=1-(1-ZP)/XP
+        XTSQ=4*(1-XP)*(1-ZP)*ZP/XP
+        XT=SQRT(XTSQ)
+        SIN1=XT/SQRT(X1**2+XTSQ)
+        SIN2=XT/SQRT(X2**2+XTSQ)
+C---CHOOSE THE AZIMUTH BETWEEN THE TWO PLANES
+        IF (BGF) THEN
+          W1=XP**2*(X1**2+1.5*XTSQ)
+        ELSE
+          W1=1
+        ENDIF
+        W2=XP**2*(X2**2+1.5*XTSQ)
+        IF (HWR()*(W1+W2).GT.W2) THEN
+          IF (BGF) THEN
+C-----WEIGHTED BY (1+SIN1*COS(PHI))**2
+ 200        PHI=(2*HWR()-1)*PIFAC
+            IF (HWR()*(1+SIN1)**2.GT.(1+SIN1*COS(PHI))**2) GOTO 200
+          ELSE
+C-----UNIFORMLY
+            PHI=(2*HWR()-1)*PIFAC
+          ENDIF
+        ELSE
+C-----WEIGHTED BY (1-SIN2*COS(PHI))**2
+ 210      PHI=(2*HWR()-1)*PIFAC
+          IF (HWR()*(1+SIN2)**2.GT.(1-SIN2*COS(PHI))**2) GOTO 210
+        ENDIF
+C---RECONSTRUCT MOMENTA AND BOOST BACK TO LAB
+        P1(1)=0
+        P1(2)=0
+        P1(3)=HALF*Q/XP
+        P1(4)=SQRT(P1(3)**2+P1(5)**2)
+        PTSQ=((ZP*Q*(P1(4)+P1(3)-Q)-P2(5)**2)*(P1(4)-P1(3)+(1-ZP)*Q)
+     $       -P3(5)**2*ZP*Q)/(P1(4)-P1(3)+Q)
+C---CHECK INFRARED CUTOFF FOR THIS PARTON TYPE
+        IF (PTSQ.LT.MAX(HWBVMC(ID),HWBVMC(IDHW(IOUT)))**2) RETURN
+        P2(1)=SQRT(PTSQ)*COS(PHI)
+        P2(2)=SQRT(PTSQ)*SIN(PHI)
+        P2(3)=-0.5*(ZP*Q-(PTSQ+P2(5)**2)/(ZP*Q))
+        P2(4)= 0.5*(ZP*Q+(PTSQ+P2(5)**2)/(ZP*Q))
+        P3(1)=P1(1)-P2(1)
+        P3(2)=P1(2)-P2(2)
+        P3(3)=P1(3)-P2(3)-Q
+        P3(4)=P1(4)-P2(4)
+        CALL HWUROB(R,P1,P1)
+        CALL HWUROB(R,P2,P2)
+        CALL HWUROB(R,P3,P3)
+        CALL HWULOB(PCMF,P1,P1)
+        CALL HWULOB(PCMF,P2,P2)
+        CALL HWULOB(PCMF,P3,P3)
+C---SPECIAL CASE FOR DIRECT PHOTON - COPY THE EXACT BEAM MOMENTUM
+C---SHARE THE MISMATCH EQUALLY BETWEEN THE OUTGOING PARTONS
+C---AND PUT THEM BACK ON SHELL
+        IF (XP.EQ.XBJ) THEN
+          CALL HWVDIF(4,PHEP(1,IHAD),P1,PM)
+          CALL HWVSCA(4,HALF,PM,PM)
+          CALL HWVSUM(4,PM,P2,P2)
+          CALL HWVSUM(4,PM,P3,P3)
+          CALL HWUMAS(P2)
+          CALL HWUMAS(P3)
+          CALL HWVEQU(5,PHEP(1,IHAD),P1)
+          CALL HWVSUM(4,P2,P3,PCMF)
+          CALL HWUMAS(PCMF)
+          POLD=HWULDO(P2,PCMF)**2/PCMF(5)**2-SIGN(P2(5)**2,P2(5))
+          PNEW=PCMF(5)**2/4-RMASS(ID)**2
+          IF (PCMF(5).LE.ZERO.OR.POLD.LE.ZERO.OR.PNEW.LE.ZERO) RETURN
+          CALL HWVSCA(4,SQRT(PNEW/POLD),P2,P2)
+          CALL HWVSCA(4,HALF-HWULDO(P2,PCMF)/PCMF(5)**2,PCMF,PM)
+          CALL HWVSUM(4,PM,P2,P2)
+          CALL HWUMAS(P2)
+          CALL HWVDIF(4,PCMF,P2,P3)
+          CALL HWUMAS(P3)
+        ENDIF
+        NHEP=NHEP+1
+        CALL HWVEQU(5,P1,PHEP(1,IIN))
+        IF (BGF.AND.ID.GT.6.OR..NOT.BGF.AND.ID.LT.7) THEN
+          CALL HWVEQU(5,P2,PHEP(1,IOUT))
+          CALL HWVEQU(5,P3,PHEP(1,NHEP))
+        ELSE
+          CALL HWVEQU(5,P3,PHEP(1,IOUT))
+          CALL HWVEQU(5,P2,PHEP(1,NHEP))
+        ENDIF
+        CALL HWVSUM(4,PHEP(1,ILEP),PHEP(1,IIN),PHEP(1,ICMF))
+        CALL HWUMAS(PHEP(1,ICMF))
+C Decide which quark radiated and assign production vertices
+        IF (BGF) THEN
+C Boson-Gluon fusion case
+          IF (1-ZP.LT.HWR()) THEN
+C Gluon splitting to quark
+            CALL HWVZRO(4,VHEP(1,NHEP-1))
+            CALL HWVDIF(4,PHEP(1,NHEP-4),PHEP(1,NHEP),PVRT)
+            CALL HWUDKL(ID,PVRT,VHEP(1,NHEP))
+            CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,NHEP-4))
+          ELSE
+C Gluon splitting to antiquark
+            CALL HWVZRO(4,VHEP(1,NHEP))
+            CALL HWVDIF(4,PHEP(1,NHEP-4),PHEP(1,NHEP-1),PVRT)
+            CALL HWUDKL(ID,PVRT,VHEP(1,NHEP-1))
+            CALL HWVEQU(4,VHEP(1,NHEP-1),VHEP(1,NHEP-4))
+          ENDIF
+        ELSE
+C QCD Compton case
+          IF (1.LT.HWR()*(1+(1-XP-ZP)**2+6*XP*(1-XP)*ZP*(1-ZP)))THEN
+C Incoming quark radiated the gluon
+            CALL HWVZRO(4,VHEP(1,NHEP-1))
+            CALL HWVDIF(4,PHEP(1,NHEP-4),PHEP(1,NHEP),PVRT)
+            CALL HWUDKL(ID,PVRT,VHEP(1,NHEP))
+            CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,NHEP-4))
+          ELSE
+C Outgoing quark radiated the gluon
+            CALL HWVZRO(4,VHEP(1,NHEP-4))
+            CALL HWVSUM(4,PHEP(1,NHEP-1),PHEP(1,NHEP),PVRT)
+            CALL HWUDKL(ID,PVRT,VHEP(1,NHEP))
+            CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,NHEP-1))
+          ENDIF
+        ENDIF
+C---STATUS, ID AND POINTERS
+        ISTHEP(NHEP)=114
+        IF (BGF) THEN
+          IF (XP.EQ.XBJ) THEN
+            IDHW(IIN)=59
+            IDHEP(IIN)=IDPDG(59)
+          ELSE
+            IDHW(IIN)=13
+            IDHEP(IIN)=IDPDG(13)
+          ENDIF
+          IF (ID.LT.7) THEN
+            IDHW(NHEP)=IDHW(IOUT)
+            IDHEP(NHEP)=IDHEP(IOUT)
+            IDHW(IOUT)=MOD(ID,6)+6
+            IDHEP(IOUT)=IDPDG(IDHW(IOUT))
+          ELSE
+            IDHW(NHEP)=MOD(ID,6)
+            IDHEP(NHEP)=IDPDG(IDHW(NHEP))
+          ENDIF
+        ELSEIF (ID.LT.7) THEN
+          IDHW(NHEP)=13
+          IDHEP(NHEP)=IDPDG(13)
+        ELSE
+          IDHW(NHEP)=IDHW(IOUT)
+          IDHEP(NHEP)=IDHEP(IOUT)
+          IDHW(IOUT)=13
+          IDHEP(IOUT)=IDPDG(13)
+        ENDIF
+        JDAHEP(2,ICMF)=NHEP
+        JMOHEP(1,NHEP)=ICMF
+C---COLOUR CONNECTIONS
+        IF (XP.EQ.XBJ) THEN
+          JMOHEP(2,IIN)=IIN
+          JDAHEP(2,IIN)=IIN
+          JMOHEP(2,IOUT)=NHEP
+          JDAHEP(2,IOUT)=NHEP
+          JMOHEP(2,NHEP)=IOUT
+          JDAHEP(2,NHEP)=IOUT
+        ELSE
+          JDAHEP(2,IIN)=NHEP
+          JDAHEP(2,NHEP)=IOUT
+          JMOHEP(2,IOUT)=NHEP
+          JMOHEP(2,NHEP)=IIN
+        ENDIF
+C---FACTORISATION SCALE
+        EMSCA=SCALE
+        EMIT=NEVHEP+NWGTS
+      ELSEIF (IOPT.EQ.2) THEN
+C---MAKE TWO-JET EVENTS LOOK LIKE ONE-JET EVENTS
+        IF (EMIT.NE.NEVHEP+NWGTS .OR. XP.EQ.XBJ) RETURN
+        IF (.NOT.BGF) THEN
+          CALL HWVEQU(5,Q1,PHEP(1,IIN))
+          CALL HWVEQU(5,Q2,PHEP(1,IOUT))
+          JMOHEP(2,IIN)=IOUT
+          JDAHEP(2,IIN)=IOUT
+          JMOHEP(2,IOUT)=IIN
+          JDAHEP(2,IOUT)=IIN
+          JDAHEP(2,ICMF)=IOUT
+          IHEP=JDAHEP(1,IOUT)
+          JHEP=JDAHEP(1,IOUT+1)
+          CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,JHEP),PHEP(1,IHEP))
+          CALL HWUMAS(PHEP(1,IHEP))
+          JDAHEP(2,IHEP)=JDAHEP(2,JHEP)
+          IEDT(1)=IOUT+1
+          IEDT(2)=JHEP
+          IEDT(3)=JHEP+1
+          NDEL=3
+          IF (ISTHEP(JHEP+1).NE.100) NDEL=2
+          IHEP=JDAHEP(1,IOUT)
+          JMOHEP(1,IHEP)=IOUT
+          IF (ISTHEP(IHEP+1).EQ.100) THEN
+            JMOHEP(1,IHEP+1)=IOUT
+            JMOHEP(2,IHEP+1)=IIN
+          ENDIF
+          DO 300 JHEP=JDAHEP(1,IHEP),JDAHEP(2,IHEP)
+            JMOHEP(1,JHEP)=IHEP
+ 300      CONTINUE
+          IF (IDHW(IOUT).EQ.13) IDHW(IOUT)=IDHW(IOUT+1)
+          IDHEP(IOUT)=IDPDG(IDHW(IOUT))
+          IDHW(IHEP)=IDHW(IOUT)
+          CALL HWUEDT(NDEL,IEDT)
+        ELSEIF (ID.LT.7) THEN
+          CALL HWVEQU(5,Q1,PHEP(1,IIN))
+          CALL HWVEQU(5,Q2,PHEP(1,IOUT+1))
+          JMOHEP(2,IIN)=IOUT+1
+          JDAHEP(2,IIN)=IOUT+1
+          JMOHEP(2,IOUT+1)=IIN
+          JDAHEP(2,IOUT+1)=IIN
+          JDAHEP(2,ICMF)=IOUT+1
+          IHEP=JDAHEP(1,IIN)
+          JHEP=JDAHEP(1,IOUT)
+          CALL HWVDIF(4,PHEP(1,IHEP),PHEP(1,JHEP),PHEP(1,IHEP))
+          CALL HWUMAS(PHEP(1,IHEP))
+          CALL HWVDIF(4,PHEP(1,ICMF),PHEP(1,JHEP),PHEP(1,ICMF))
+          CALL HWUMAS(PHEP(1,ICMF))
+          CALL HWUEMV(JDAHEP(2,JHEP)-JDAHEP(1,JHEP)+1,
+     $         JDAHEP(1,JHEP),JDAHEP(2,IHEP))
+          JHEP=JDAHEP(1,IOUT)
+          JDAHEP(2,IHEP)=JDAHEP(2,JHEP)
+          IEDT(1)=IOUT
+          IEDT(2)=JHEP
+          IEDT(3)=JHEP+1
+          NDEL=3
+          IF (ISTHEP(JHEP+1).NE.100) NDEL=2
+          CALL HWUEDT(NDEL,IEDT)
+          IHEP=JDAHEP(1,IIN)
+          DO 400 JHEP=JDAHEP(1,IHEP),JDAHEP(2,IHEP)
+            JMOHEP(1,JHEP)=IHEP
+ 400      CONTINUE
+          IDHW(IIN)=ID
+          IDHEP(IIN)=IDPDG(ID)
+          IDHW(IHEP)=ID
+        ELSE
+          CALL HWVEQU(5,Q1,PHEP(1,IIN))
+          CALL HWVEQU(5,Q2,PHEP(1,IOUT))
+          JMOHEP(2,IIN)=IOUT
+          JDAHEP(2,IIN)=IOUT
+          JMOHEP(2,IOUT)=IIN
+          JDAHEP(2,IOUT)=IIN
+          JDAHEP(2,ICMF)=IOUT
+          IHEP=JDAHEP(1,IIN)
+          JHEP=JDAHEP(1,IOUT+1)
+          CALL HWVDIF(4,PHEP(1,IHEP),PHEP(1,JHEP),PHEP(1,IHEP))
+          CALL HWUMAS(PHEP(1,IHEP))
+          CALL HWVDIF(4,PHEP(1,ICMF),PHEP(1,JHEP),PHEP(1,ICMF))
+          CALL HWUMAS(PHEP(1,ICMF))
+          CALL HWUEMV(JDAHEP(2,JHEP)-JDAHEP(1,JHEP)+1,
+     $         JDAHEP(1,JHEP),JDAHEP(1,IHEP)-1)
+          JHEP=JDAHEP(1,IOUT+1)
+          JDAHEP(1,IHEP)=JDAHEP(1,JHEP)
+          IEDT(1)=IOUT+1
+          IEDT(2)=JHEP
+          IEDT(3)=JHEP+1
+          NDEL=3
+          IF (ISTHEP(JHEP+1).NE.100.OR.JHEP.EQ.NHEP) NDEL=2
+          CALL HWUEDT(NDEL,IEDT)
+          IHEP=JDAHEP(1,IIN)
+          DO 500 JHEP=JDAHEP(1,IHEP),JDAHEP(2,IHEP)
+            JMOHEP(1,JHEP)=IHEP
+ 500      CONTINUE
+          IDHW(IIN)=ID
+          IDHEP(IIN)=IDPDG(ID)
+          IDHW(IHEP)=ID
+        ENDIF
+        CALL HWVZRO(4,VHEP(1,IIN))
+        CALL HWVZRO(4,VHEP(1,JDAHEP(1,IIN)))
+        IF (ISTHEP(JDAHEP(1,IIN)+1).EQ.100)
+     $       CALL HWVZRO(4,VHEP(1,JDAHEP(1,IIN)+1))
+        CALL HWVZRO(4,VHEP(1,IOUT))
+        CALL HWVZRO(4,VHEP(1,JDAHEP(1,IOUT)))
+        IF (ISTHEP(JDAHEP(1,IOUT)+1).EQ.100)
+     $       CALL HWVZRO(4,VHEP(1,JDAHEP(1,IOUT)+1))
+        EMIT=0
+      ELSE
+        CALL HWWARN('HWBDIS',500,*999)
+      ENDIF
+ 999  END
+CDECK  ID>, HWBDYP.
+*CMZ :-        -26/10/99  17.46.56  by  Mike Seymour
+*-- Author :    Gennaro Corcella
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBDYP(IOPT)
+C     MATRIX ELEMENT CORRECTIONS TO DRELL-YAN PROCESSES
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBVMC,HWR,HWUALF,HWUSQR,PMODK,AZ,CZ,
+     & T,U,S,EM,TMIN,TMAX,PMOD2,GLUFAC,SMIN,SMAX,SZ,TEST,
+     & JAC,M(3),W1,W,PMOD3,SCAPR,CPHI,SPHI,SCALE,XI1,XI2,
+     & PDFOLD1(13),PDFOLD2(13),PDFNEW1(13),PDFNEW2(13),ETA1,ETA2,Y,
+     & COMWGT1,COMWGT2,WW,COS3,MODP,RN,BETA1,SIN3,R3(3,3),CTH,STH,M1,
+     & M2,M3,GAMMA1,R5(3,3),CW,SW,R4(3,3),SCALE1,X1,X2,X3,MM,
+     & PHAD1(5),PHAD2(5),P1(5),P2(5),P3(5),P4(5),PF(5),PV(5),PK(5),
+     & PR(5),PNE(5),PE(5),PP1(5),PP2(5),PZ(5),PS(5),PD(5),P2N(5),
+     & PBOS(5),PLAB(5),PTOT(5),P3N(5),SVNTN
+      LOGICAL GLUIN,GP
+      INTEGER EMIT,NOEMIT,IHEP,JHEP,KHEP,ICMF,IOPT,CHEP,
+     & ID2,ID1,K,ID4,ID5,IDBOS,IHAD1,IHAD2,NTMP
+      EXTERNAL HWBVMC,HWR,HWUALF,HWUSQR
+      SAVE ICMF,ID4,ID5
+      DATA EMIT,NTMP/2*0/
+      IF (IOPT.EQ.1) THEN
+        EMIT=0
+        NTMP=0
+C-----CHOOSE WEIGHTS
+        COMWGT1=0.1
+        COMWGT2=0.55
+C---FIND AN UNTREATED CMF
+        ICMF=0
+        DO 10 IHEP=1,NHEP
+ 10     IF (ICMF.EQ.0 .AND. ISTHEP(IHEP).EQ.110.AND.
+     &         JDAHEP(2,IHEP).EQ.JDAHEP(1,IHEP)+1) ICMF=IHEP
+        IF (ICMF.EQ.0) RETURN
+        EM=PHEP(5,ICMF)
+C-----SET THE VECTOR BOSON RAPIDITY
+        Y=HALF*LOG((PHEP(4,ICMF)+PHEP(3,ICMF))/
+     &       (PHEP(4,ICMF)-PHEP(3,ICMF)))
+C------SET PARTICLE IDENTIES
+c------ID1=QUARK, ID2=ANTIQUARK, IDBOS=VECTOR BOSON, ID4-5 BOSON DECAY
+        IDBOS=IDHW(ICMF)
+        ID1=IDHW(JMOHEP(1,ICMF))
+        ID2=IDHW(JMOHEP(2,ICMF))
+        ID4=IDHW(JDAHEP(1,ICMF))
+        ID5=IDHW(JDAHEP(2,ICMF))
+        M1=RMASS(ID1)
+        M2=RMASS(ID2)
+        M3=RMASS(13)
+C---STORE OLD MOMENTA
+C------VECTOR BOSON MOMENTUM
+        CALL HWVEQU(5,PHEP(1,ICMF),PBOS)
+C----QUARK MOMENTUM
+        CALL HWVEQU(5,PHEP(1,JMOHEP(1,ICMF)),P1)
+C------ANTIQUARK MOMENTUM
+        CALL HWVEQU(5,PHEP(1,JMOHEP(2,ICMF)),P2)
+C-------VECTOR DECAY (LEPTON) PRODUCT MOMENTA
+        CALL HWVEQU(5,PHEP(1,JDAHEP(1,ICMF)),P3)
+        CALL HWVEQU(5,PHEP(1,JDAHEP(2,ICMF)),P4)
+C------LEPTON MOMENTA IN THE BOSON REST FRAME
+        CALL HWULOF(PHEP(1,ICMF),P2,P2N)
+        CALL HWULOF(PHEP(1,ICMF),P3,P3N)
+C------AZ=AZIMUTHAL ANGLE OF P3N
+        AZ=ATAN2(P3N(2),P3N(1))
+        CZ=COS(AZ)
+        SZ=SIN(AZ)
+C------PHI=ANGLE BETWEEN P2N AND P3N
+        SCAPR=P2N(1)*P3N(1)+P2N(2)*P3N(2)+P2N(3)*P3N(3)
+        PMOD2=SQRT(P2N(1)**2+P2N(2)**2+P2N(3)**2)
+        PMOD3=SQRT(P3N(1)**2+P3N(2)**2+P3N(3)**2)
+        CPHI=SCAPR/(PMOD3*PMOD2)
+        SPHI=SQRT(1-CPHI**2)
+C------HADRON MOMENTA
+        IHAD1=1
+        IHAD2=2
+        IF (JDAHEP(1,IHAD1).NE.0) IHAD1=JDAHEP(1,IHAD1)
+        IF (JDAHEP(1,IHAD2).NE.0) IHAD2=JDAHEP(1,IHAD2)
+        CALL HWVEQU(5,PHEP(1,IHAD1),PHAD1)
+        CALL HWVEQU(5,PHEP(1,IHAD2),PHAD2)
+        CALL HWVSUM(4,PHAD1,PHAD2,PTOT)
+        CALL HWUMAS(PTOT)
+C------ Q - QBAR ENERGY FRACTIONS (BORN PROCESS)
+        ETA1=P1(4)/PHAD1(4)
+        ETA2=P2(4)/PHAD2(4)
+C------ PDFs FOR THE BORN PROCESS
+        CALL HWSFUN(ETA1,EM,IDHW(IHAD1),NSTRU,PDFOLD1,1)
+        CALL HWSFUN(ETA2,EM,IDHW(IHAD2),NSTRU,PDFOLD2,2)
+C-------CONSIDER Q(QBAR) IN THE INITIAL STATE
+        RN=HWR()
+        IF (RN.LT.COMWGT1) THEN
+C-------NO GLUON IN THE INITIAL STATE
+          GLUIN=.FALSE.
+C---CHOOSE S ACCORDING TO 1/S**2
+          SVNTN=17
+          SMIN=HALF*EM**2*(7-SQRT(SVNTN))
+          SMAX=PTOT(5)**2
+          IF (SMAX.LE.SMIN) RETURN
+          S=SMIN*SMAX/(SMIN+HWR()*(SMAX-SMIN))
+          JAC=S**2*(1/SMIN-1/SMAX)
+C---CHOOSE T ACCORDING TO (S-EM**2)/(T*U)=1/T+1/U
+          TMAX=-HALF*EM**2*(3-HWUSQR(1+8*EM**2/S))
+          TMIN=EM**2-S-TMAX
+          IF (TMAX.LE.TMIN) RETURN
+          T=TMAX*(TMIN/TMAX)**HWR()
+          IF (HWR().GT.HALF) T=EM**2-S-T
+          U=EM**2-S-T
+          JAC=JAC*2*T*U/(S-EM**2)*LOG(TMIN/TMAX)
+          SCALE=SQRT(U*T/S)
+          SCALE1=SQRT(U*T/S+EM**2)
+          GLUFAC=0
+          IF (SCALE1.GT.HWBVMC(13)) GLUFAC=HWUALF(1,SCALE1)/(2*PIFAC)
+C----Q-QBAR ENERGY FRACTIONS FOR Q QBAR-> VG
+          XI1=(HALF/PHAD1(4))*EXP(Y)*SQRT(S*(S+T)/(S+U))
+          XI2=S/(4*XI1*PHAD1(4)*PHAD2(4))
+          IF (XI1.GE.1.OR.XI2.GE.1) RETURN
+C-----PDFs WITH AN EMITTED GLUON
+          CALL HWSFUN(XI1,SCALE,IDHW(IHAD1),NSTRU,PDFNEW1,1)
+          CALL HWSFUN(XI2,SCALE,IDHW(IHAD2),NSTRU,PDFNEW2,2)
+C------CALCULATE WEIGHT
+          W=JAC*((EM**2-T)**2+(EM**2-U)**2)/(S**2*T*U)
+          W1=(GLUFAC/COMWGT1)*W*PDFNEW1(ID1)*PDFNEW2(ID2)/(PDFOLD1(ID1)*
+     &         PDFOLD2(ID2))*(CFFAC*ETA1*ETA2/(XI1*XI2))
+C-------CHOOSE WHICH PARTON WILL EMIT
+          EMIT=1
+          IF (HWR().LT.(EM**2-U)**2/((EM**2-U)**2+(EM**2-T)**2))
+     &         EMIT=2
+          NOEMIT=3-EMIT
+        ELSE
+C--------GLUON IN THE INITIAL STATE
+          GLUIN=.TRUE.
+C---CHOOSE S ACCORDING TO 1/S**2
+          SMIN=EM**2
+          SMAX=PTOT(5)**2
+          IF (SMAX.LE.SMIN) RETURN
+          S=SMIN*SMAX/(SMIN+HWR()*(SMAX-SMIN))
+          JAC=S**2*(1/SMIN-1/SMAX)
+C---CHOOSE T ACCORDING TO 1/T
+          TMAX=-HALF*EM**2*(3-HWUSQR(1+8*EM**2/S))
+          TMIN=EM**2-S
+          IF (TMAX.LE.TMIN) RETURN
+          T=TMAX*(TMIN/TMAX)**HWR()
+          JAC=JAC*T*LOG(TMAX/TMIN)
+          U=EM**2-S-T
+          SCALE=SQRT(U*T/S)
+          SCALE1=SQRT(U*T/S+EM**2)
+          GLUFAC=0
+          IF (SCALE1.GT.HWBVMC(13)) GLUFAC=HWUALF(1,SCALE1)/(2*PIFAC)
+C--------INITIAL STATE GLUON COMING FROM HADRON 1
+          IF (RN.LE.COMWGT2) THEN
+            GP=.TRUE.
+C--------ENERGY FRACTIONS and PDFs
+            XI1=(HALF/PHAD1(4))*EXP(Y)*SQRT(S*(S+U)/(S+T))
+            XI2=S/(4*XI1*PHAD1(4)*PHAD2(4))
+            IF (XI1.GE.1.OR.XI2.GE.1) RETURN
+            CALL HWSFUN(XI1,SCALE,IDHW(IHAD1),NSTRU,PDFNEW1,1)
+            CALL HWSFUN(XI2,SCALE,IDHW(IHAD2),NSTRU,PDFNEW2,2)
+            WW=PDFNEW1(13)*PDFNEW2(ID2)/((COMWGT2-COMWGT1)*
+     &           PDFOLD1(ID1)*PDFOLD2(ID2))
+          ELSE
+C-------INITIAL STATE GLUON COMING FROM HADRON 2
+            GP=.FALSE.
+C-------ENERGY FRACTIONS AND PDFs
+            XI1=(HALF/PHAD1(4))*EXP(Y)*SQRT(S*(S+T)/(S+U))
+            XI2=S/(4*XI1*PHAD1(4)*PHAD2(4))
+            IF (XI1.GE.1.OR.XI2.GE.1) RETURN
+            CALL HWSFUN(XI1,SCALE,IDHW(IHAD1),NSTRU,PDFNEW1,1)
+            CALL HWSFUN(XI2,SCALE,IDHW(IHAD2),NSTRU,PDFNEW2,2)
+            WW=PDFNEW1(ID1)*PDFNEW2(13)/((1-COMWGT2)*
+     &           PDFOLD1(ID1)*PDFOLD2(ID2))
+          ENDIF
+          W=-HALF*JAC*((EM**2-T)**2+(EM**2-S)**2)/(S**3*T)
+C-------CHOOSE WHICH PARTON WILL EMIT
+          EMIT=1
+          IF (HWR().LT.(EM**2-S)**2/((EM**2-S)**2+(EM**2-T)**2))
+     &         EMIT=2
+          NOEMIT=3-EMIT
+C-------FINAL WEIGHT FOR ALL THE CONSIDERED OPTIONS
+          W1=GLUFAC*W*WW*ETA1*ETA2/(XI1*XI2)
+        ENDIF
+C--------ADD ONE MORE GLUON
+        IF (W1.GT.HWR()) THEN
+          NTMP=NEVHEP+NWGTS
+        ELSE
+          RETURN
+        ENDIF
+C---------INCLUDE MASSES
+        S=S+M1**2+M2**2+M3**2
+        IF (.NOT.GLUIN) THEN
+          TEST=((S+M1**2-M2**2)*(S+M3**2-EM**2)-2*S*(M1**2+M3**2-T))**2
+     $         -((S-M1**2-M2**2)**2-4*M1**2*M2**2)*
+     $         ((S-M3**2-EM**2)**2-4*M3**2*EM**2)
+        ELSEIF (GP) THEN
+          TEST=((S+M3**2-M2**2)*(S+M1**2-EM**2)-2*S*(M3**2+M1**2-T))**2
+     $         -((S-M3**2-M2**2)**2-4*M3**2*M2**2)*
+     $         ((S-M1**2-EM**2)**2-4*M1**2*EM**2)
+        ELSE
+          TEST=((S+M3**2-M1**2)*(S+M2**2-EM**2)-2*S*(M3**2+M2**2-T))**2
+     $         -((S-M3**2-M1**2)**2-4*M3**2*M1**2)*
+     $         ((S-M2**2-EM**2)**2-4*M2**2*EM**2)
+        ENDIF
+        IF (TEST.GE.0) THEN
+          EMIT=0
+          RETURN
+        ENDIF
+        M(1)=M1
+        M(2)=M2
+        M(3)=M3
+C----MOMENTA IN THE V-REST FRAME WITH NON EMITTER ALONG THE Z AXIS
+C----V=BOSON,K=GLUON,E=EMITTER,NE=NON-EMITTER
+        PV(1)=0
+        PV(2)=0
+        PV(3)=0
+        PV(4)=EM
+        PV(5)=EM
+        PNE(2)=0
+        PNE(1)=0
+        IF (.NOT.GLUIN) THEN
+          PK(4)=(S-M(3)**2-EM**2)/(2*EM)
+          PMODK=SQRT(PK(4)**2-M(3)**2)
+          IF (EMIT.EQ.1) THEN
+            MM=M(1)
+            X1=T
+            X2=U
+            X3=-1
+          ELSE
+            MM=M(2)
+            X1=U
+            X2=T
+            X3=+1
+          ENDIF
+          PNE(4)=(EM**2+MM**2-X1)/(2*EM)
+          PNE(3)=X3*SQRT(PNE(4)**2-MM**2)
+          COS3=HALF*(X2-MM**2-M(3)**2+2*PNE(4)*PK(4))/(PNE(3)*PMODK)
+        ELSE
+          PK(4)=(EM**2+M(3)**2-U)/(2*EM)
+          PMODK=SQRT(PK(4)**2-M(3)**2)
+          IF (EMIT.EQ.1) THEN
+            IF (GP) THEN
+              MM=M(1)
+              X3=+1
+            ELSE
+              MM=M(2)
+              X3=-1
+            ENDIF
+            PNE(4)=(S-MM**2-EM**2)/(2*EM)
+            PNE(3)=X3*SQRT(PNE(4)**2-MM**2)
+            COS3=HALF*(T-MM**2-M(3)**2+2*PNE(4)*PK(4))/(PNE(3)*PMODK)
+          ELSE
+            IF (GP) THEN
+              MM=M(2)
+              X3=-1
+            ELSE
+              MM=M(1)
+              X3=+1
+            ENDIF
+            PNE(4)=(EM**2+MM**2-T)/(2*EM)
+            PNE(3)=X3*SQRT(PNE(4)**2-MM**2)
+            COS3=HALF*(MM**2+M(3)**2-S+2*PNE(4)*PK(4))/(PNE(3)*PMODK)
+          ENDIF
+        ENDIF
+        CALL HWUMAS(PNE)
+        SIN3=SQRT(1-COS3**2)
+C---------DEFINE A RANDOM ROTATION AROUND THE Z-AXIS
+        CALL HWRAZM(PMODK*SIN3,PK(1),PK(2))
+        PK(3)=PMODK*COS3
+        CALL HWUMAS(PK)
+        DO K=1,4
+          IF (.NOT.GLUIN) THEN
+            PE(K)=PV(K)+PK(K)-PNE(K)
+          ELSE
+            IF (EMIT.EQ.1) THEN
+              PE(K)=PV(K)+PNE(K)-PK(K)
+            ELSE
+              PE(K)=PNE(K)+PK(K)-PV(K)
+            ENDIF
+          ENDIF
+        ENDDO
+        CALL HWUMAS(PE)
+c------LEPTON MOMENTA IN THE BOSON REST FRAME, WITH THE DIRECTION
+C------TAKEN FROM THE BORN PROCESS
+        PS(5)=P3(5)
+        PS(4)=(EM**2+P3(5)**2-P4(5)**2)/(2*EM)
+        PS(3)=-SQRT(PS(4)**2-P3(5)**2)*CPHI
+        PS(2)=SQRT(PS(4)**2-P3(5)**2)*SPHI*SZ
+        PS(1)=SQRT(PS(4)**2-P3(5)**2)*SPHI*CZ
+        PF(5)=P4(5)
+        PF(4)=(EM**2+P4(5)**2-P3(5)**2)/(2*EM)
+        PF(3)=-PS(3)
+        PF(2)=-PS(2)
+        PF(1)=-PS(1)
+C----FIND A STATIONARY VECTOR PLAB IN THE LAB FRAME
+        IF (.NOT.GLUIN) THEN
+          IF (EMIT.EQ.1) THEN
+            CALL HWVEQU(5,PE,PP1)
+            CALL HWVEQU(5,PNE,PP2)
+          ELSE
+            CALL HWVEQU(5,PNE,PP1)
+            CALL HWVEQU(5,PE,PP2)
+          ENDIF
+        ELSE
+          IF (GP) THEN
+            CALL HWVEQU(5,PK,PP1)
+            IF (EMIT.EQ.1) THEN
+              CALL HWVEQU(5,PE,PP2)
+            ELSE
+              CALL HWVEQU(5,PNE,PP2)
+            ENDIF
+          ELSE
+            CALL HWVEQU(5,PK,PP2)
+            IF (EMIT.EQ.1) THEN
+              CALL HWVEQU(5,PE,PP1)
+            ELSE
+              CALL HWVEQU(5,PNE,PP1)
+            ENDIF
+          ENDIF
+        ENDIF
+        CALL HWVSCA(4,1/XI1,PP1,PP1)
+        CALL HWVSCA(4,1/XI2,PP2,PP2)
+        CALL HWVSUM(4,PP1,PP2,PLAB)
+        CALL HWUMAS(PLAB)
+C------BOOST TO PLAB REST FRAME
+        CALL HWULOF(PLAB,PE,PE)
+        CALL HWULOF(PLAB,PNE,PNE)
+        CALL HWULOF(PLAB,PK,PK)
+        CALL HWULOF(PLAB,PS,PS)
+        CALL HWULOF(PLAB,PF,PF)
+        CALL HWULOF(PLAB,PV,PV)
+C----PUT THE INITIAL PARTON BELONGING TO HADRON 1 ON THE Z-AXIS
+        IF (.NOT.GLUIN) THEN
+          IF (EMIT.EQ.1) THEN
+            CALL HWVEQU(5,PE,PZ)
+          ELSE
+            CALL HWVEQU(5,PNE,PZ)
+          ENDIF
+        ELSE
+          IF (GP) THEN
+            CALL HWVEQU(5,PK,PZ)
+          ELSE
+            IF (EMIT.EQ.1) THEN
+              CALL HWVEQU(5,PE,PZ)
+            ELSE
+              CALL HWVEQU(5,PNE,PZ)
+            ENDIF
+          ENDIF
+        ENDIF
+        MODP=SQRT(PZ(1)**2+PZ(2)**2)
+        CTH=PZ(1)/MODP
+        STH=PZ(2)/MODP
+        CALL HWUROT(PZ,CTH,STH,R3)
+C-----ROTATE EVERYTHING BY R3
+        CALL HWUROF(R3,PE,PE)
+        CALL HWUROF(R3,PNE,PNE)
+        CALL HWUROF(R3,PV,PV)
+        CALL HWUROF(R3,PK,PK)
+        CALL HWUROF(R3,PS,PS)
+        CALL HWUROF(R3,PF,PF)
+C--REORDER ENTRIES:--IHEP=EMITTER,JHEP=NON-EMITTER,KHEP=EMITTED
+        IF (.NOT.GLUIN) THEN
+          IHEP=JMOHEP(EMIT,ICMF)
+          JHEP=JMOHEP(NOEMIT,ICMF)
+        ENDIF
+        CHEP=ICMF
+        IDHW(CHEP)=15
+        IDHEP(CHEP)=IDPDG(15)
+        ICMF=ICMF+1
+        IDHW(ICMF)=IDBOS
+        IDHEP(ICMF)=IDPDG(IDBOS)
+C-----NO GLUON IN THE INITIAL STATE: JUST ADD IT AFTER THE VECTOR BOSON
+        IF (.NOT.GLUIN) THEN
+          KHEP=ICMF+1
+          ISTHEP(KHEP)=114
+C---STATUS OF EMITTER/NON EMITTER
+          ISTHEP(IHEP)=110+EMIT
+          ISTHEP(JHEP)=110+NOEMIT
+        ELSE
+C-----GLUON COMING FROM THE 1ST HADRON
+          IF (GP) THEN
+            KHEP=CHEP-2
+            ISTHEP(KHEP)=111
+C----EMIT=1
+            IF (EMIT.EQ.1) THEN
+              IHEP=KHEP+1
+              ISTHEP(IHEP)=112
+              JHEP=ICMF+1
+              ISTHEP(JHEP)=114
+              IDHW(IHEP)=ID2
+              IF (ID1.LE.6) THEN
+                IDHW(JHEP)=ID1+6
+              ELSE
+                IDHW(JHEP)=ID1-6
+              ENDIF
+            ELSE
+C-------EMIT=2
+              JHEP=KHEP+1
+              ISTHEP(JHEP)=112
+              IDHW(JHEP)=ID2
+              IHEP=ICMF+1
+              ISTHEP(IHEP)=114
+              IF (ID1.LE.6) THEN
+                IDHW(IHEP)=ID1+6
+              ELSE
+                IDHW(IHEP)=ID1-6
+              ENDIF
+            ENDIF
+          ENDIF
+C------GLUON COMING FROM THE HADRON 2
+          IF (.NOT.GP) THEN
+            KHEP=CHEP-1
+            ISTHEP(KHEP)=112
+C-------EMIT=1
+            IF (EMIT.EQ.1) THEN
+              IHEP=KHEP-1
+              ISTHEP(IHEP)=111
+              IDHW(IHEP)=ID1
+              JHEP=ICMF+1
+              ISTHEP(JHEP)=114
+              IF (ID2.LE.6) THEN
+                IDHW(JHEP)=ID2+6
+              ELSE
+                IDHW(JHEP)=ID2-6
+              ENDIF
+            ELSE
+C-------EMIT=2
+              JHEP=KHEP-1
+              ISTHEP(JHEP)=111
+              IDHW(JHEP)=ID1
+              IHEP=ICMF+1
+              ISTHEP(IHEP)=114
+              IF (ID2.LE.6) THEN
+                IDHW(IHEP)=ID2+6
+              ELSE
+                IDHW(IHEP)=ID2-6
+              ENDIF
+            ENDIF
+          ENDIF
+        ENDIF
+        IDHEP(IHEP)=IDPDG(IDHW(IHEP))
+        IDHEP(JHEP)=IDPDG(IDHW(JHEP))
+        ISTHEP(ICMF)=113
+        ISTHEP(CHEP)=110
+        IDHW(KHEP)=13
+        IDHEP(KHEP)=IDPDG(13)
+C---------DEFINE MOMENTA IN THE LAB FRAME
+        CALL HWVEQU(5,PV,PHEP(1,ICMF))
+        CALL HWVEQU(5,PK,PHEP(1,KHEP))
+        CALL HWVEQU(5,PNE,PHEP(1,JHEP))
+        CALL HWVEQU(5,PE,PHEP(1,IHEP))
+        IF (.NOT.GLUIN) THEN
+          CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,JHEP),PHEP(1,CHEP))
+        ELSE
+          IF (EMIT.EQ.1) THEN
+            CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,KHEP),PHEP(1,CHEP))
+          ELSE
+            CALL HWVSUM(4,PHEP(1,KHEP),PHEP(1,JHEP),PHEP(1,CHEP))
+          ENDIF
+        ENDIF
+        CALL HWUMAS(PHEP(1,CHEP))
+        IF (.NOT.GLUIN) THEN
+          JMOHEP(1,JHEP)=CHEP
+          JMOHEP(1,IHEP)=CHEP
+          JDAHEP(1,JHEP)=CHEP
+          JDAHEP(1,IHEP)=CHEP
+          JMOHEP(1,KHEP)=CHEP
+          JDAHEP(1,KHEP)=0
+          JMOHEP(1,ICMF)=CHEP
+          JMOHEP(2,ICMF)=ICMF
+          JDAHEP(1,ICMF)=0
+          JDAHEP(2,ICMF)=ICMF
+        ENDIF
+        IF (GLUIN) THEN
+          JMOHEP(2,ICMF)=ICMF
+          JDAHEP(2,ICMF)=ICMF
+          JMOHEP(1,KHEP)=CHEP
+          JDAHEP(1,KHEP)=CHEP
+          JMOHEP(1,IHEP)=CHEP
+          JMOHEP(1,JHEP)=CHEP
+          IF (EMIT.EQ.1) THEN
+            JDAHEP(1,IHEP)=CHEP
+            JDAHEP(1,JHEP)=0
+          ELSE
+            JDAHEP(1,JHEP)=CHEP
+            JDAHEP(1,IHEP)=0
+          ENDIF
+        ENDIF
+C---COLOUR CONNECTIONS
+        IF (.NOT.GLUIN) THEN
+          IF (IDHW(IHEP).LT.IDHW(JHEP)) THEN
+            JMOHEP(2,KHEP)=IHEP
+            JDAHEP(2,KHEP)=JHEP
+            JMOHEP(2,IHEP)=JHEP
+            JDAHEP(2,IHEP)=KHEP
+            JDAHEP(2,JHEP)=IHEP
+            JMOHEP(2,JHEP)=KHEP
+          ELSE
+            JMOHEP(2,KHEP)=JHEP
+            JDAHEP(2,KHEP)=IHEP
+            JMOHEP(2,JHEP)=IHEP
+            JDAHEP(2,JHEP)=KHEP
+            JDAHEP(2,IHEP)=JHEP
+            JMOHEP(2,IHEP)=KHEP
+          ENDIF
+        ENDIF
+        IF (GLUIN) THEN
+          IF (EMIT.EQ.1) THEN
+            IF (IDHEP(IHEP).GT.0) THEN
+              JMOHEP(2,IHEP)=JHEP
+              JDAHEP(2,IHEP)=KHEP
+              JMOHEP(2,JHEP)=KHEP
+              JDAHEP(2,JHEP)=IHEP
+              JMOHEP(2,KHEP)=IHEP
+              JDAHEP(2,KHEP)=JHEP
+            ELSE
+              JMOHEP(2,IHEP)=KHEP
+              JDAHEP(2,IHEP)=JHEP
+              JMOHEP(2,JHEP)=IHEP
+              JDAHEP(2,JHEP)=KHEP
+              JMOHEP(2,KHEP)=JHEP
+              JDAHEP(2,KHEP)=IHEP
+            ENDIF
+          ELSE
+            IF (IDHEP(JHEP).GT.0) THEN
+              JMOHEP(2,JHEP)=IHEP
+              JDAHEP(2,JHEP)=KHEP
+              JMOHEP(2,IHEP)=KHEP
+              JDAHEP(2,IHEP)=JHEP
+              JMOHEP(2,KHEP)=JHEP
+              JDAHEP(2,KHEP)=IHEP
+            ELSE
+              JMOHEP(2,JHEP)=KHEP
+              JDAHEP(2,JHEP)=IHEP
+              JMOHEP(2,IHEP)=JHEP
+              JDAHEP(2,IHEP)=KHEP
+              JMOHEP(2,KHEP)=IHEP
+              JDAHEP(2,KHEP)=JHEP
+            ENDIF
+          ENDIF
+        ENDIF
+        EMSCA=SQRT(EM**2+PHEP(1,ICMF)**2+PHEP(2,ICMF)**2)
+C--------SET STATUS AND LEPTON MOMENTA AFTER THE PARTON SHOWER
+      ELSEIF (IOPT.EQ.2) THEN
+        IF (EMIT.EQ.0.OR.NEVHEP+NWGTS.NE.NTMP) RETURN
+        ISTHEP(JDAHEP(1,ICMF))=195
+        IDHW(NHEP+1)=ID4
+        IDHW(NHEP+2)=ID5
+        IDHEP(NHEP+1)=IDPDG(ID4)
+        IDHEP(NHEP+2)=IDPDG(ID5)
+        ISTHEP(NHEP+1)=113
+        ISTHEP(NHEP+2)=114
+        CW=PHEP(3,ICMF)/SQRT(PHEP(1,ICMF)**2+PHEP(2,ICMF)**2+
+     &       PHEP(3,ICMF)**2)
+        SW=SQRT(1-CW**2)
+        CALL HWUROT(PHEP(1,ICMF),CW,SW,R4)
+        CALL HWUROF(R4,PHEP(1,ICMF),PR)
+        PR(4)=PHEP(4,ICMF)
+        CALL HWUMAS(PR)
+        CALL HWUROF(R4,PS,PS)
+        CALL HWUROF(R4,PF,PF)
+        CALL HWUMAS(PS)
+        CALL HWUMAS(PF)
+        CALL HWUROT(PHEP(1,JDAHEP(1,ICMF)),CW,SW,R5)
+        CALL HWUROF(R5,PHEP(1,JDAHEP(1,ICMF)),PD)
+        PD(4)=PHEP(4,JDAHEP(1,ICMF))
+        CALL HWUMAS(PD)
+        BETA1=(PR(4)*PR(3)-SQRT(PR(4)**2*PD(3)**2-PR(3)**2*PD(3)**2+
+     &       PD(3)**4))/(PD(3)**2+PR(4)**2)
+        GAMMA1=1/SQRT(1-BETA1**2)
+        PHEP(4,NHEP+1)=GAMMA1*PS(4)-BETA1*GAMMA1*PS(3)
+        PHEP(3,NHEP+1)=-BETA1*GAMMA1*PS(4)+GAMMA1*PS(3)
+        PHEP(4,NHEP+2)=GAMMA1*PF(4)-BETA1*GAMMA1*PF(3)
+        PHEP(3,NHEP+2)=-BETA1*GAMMA1*PF(4)+GAMMA1*PF(3)
+        PHEP(1,NHEP+1)=PS(1)
+        PHEP(2,NHEP+1)=PS(2)
+        PHEP(1,NHEP+2)=PF(1)
+        PHEP(2,NHEP+2)=PF(2)
+        CALL HWUMAS(PHEP(1,NHEP+1))
+        CALL HWUMAS(PHEP(1,NHEP+2))
+        CALL HWUROB(R5,PHEP(1,NHEP+1),PHEP(1,NHEP+1))
+        CALL HWUROB(R5,PHEP(1,NHEP+2),PHEP(1,NHEP+2))
+        JDAHEP(1,JDAHEP(1,ICMF))=NHEP+1
+        JDAHEP(2,JDAHEP(1,ICMF))=NHEP+2
+        JMOHEP(1,NHEP+1)=JDAHEP(1,ICMF)
+        JMOHEP(1,NHEP+2)=JDAHEP(1,ICMF)
+        JMOHEP(2,NHEP+1)=NHEP+2
+        JDAHEP(2,NHEP+1)=NHEP+2
+        JMOHEP(2,NHEP+2)=NHEP+1
+        JDAHEP(2,NHEP+2)=NHEP+1
+        NHEP=NHEP+2
+        EMIT=0
+      ENDIF
+      END
+CDECK  ID>, HWBFIN.
+*CMZ :-        -26/04/91  10.18.56  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBFIN(IHEP)
+C-----------------------------------------------------------------------
+C     DELETES INTERNAL LINES FROM SHOWER, MAKES COLOUR CONNECTION INDEX
+C     AND COPIES INTO /HEPEVT/ IN COLOUR ORDER.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,ID,IJET,KHEP,IPAR,JPAR,NXPAR,IP,JP
+      IF (IERROR.NE.0) RETURN
+C---SAVE VIRTUAL PARTON DATA
+      NHEP=NHEP+1
+      IF(NHEP.GT.NMXHEP) CALL HWWARN('HWBFIN',100,*999)
+      ID=IDPAR(2)
+      IDHW(NHEP)=ID
+      IDHEP(NHEP)=IDPDG(ID)
+      ISTHEP(NHEP)=ISTHEP(IHEP)+20
+      JMOHEP(1,NHEP)=IHEP
+      JMOHEP(2,NHEP)=JMOHEP(1,IHEP)
+      JDAHEP(1,IHEP)=NHEP
+      JDAHEP(1,NHEP)=0
+      JDAHEP(2,NHEP)=0
+      CALL HWVEQU(5,PPAR(1,2),PHEP(1,NHEP))
+      CALL HWVEQU(4,VPAR(1,2),VHEP(1,NHEP))
+C---FINISHED FOR SPECTATOR OR NON-PARTON JETS
+      IF (ISTHEP(NHEP).GT.136) RETURN
+      IF (ID.GT.13.AND.ID.LT.209 .AND. ID.NE.59) RETURN
+      IF (ID.GT.220.AND.ABS(IDPDG(ID)).LT.1000000) RETURN
+      IF (ID.GT.424.AND.ID.NE.449) RETURN
+      IF (.NOT.TMPAR(2).AND.ID.EQ.59) RETURN
+      IDHEP(NHEP)=94
+      IJET=NHEP
+      IF (NPAR.GT.2) THEN
+C---SAVE CONE DATA
+        NHEP=NHEP+1
+        IF(NHEP.GT.NMXHEP) CALL HWWARN('HWBFIN',101,*999)
+        IDHW(NHEP)=IDPAR(1)
+        IDHEP(NHEP)=0
+        ISTHEP(NHEP)=100
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=JCOPAR(1,1)
+        JDAHEP(1,NHEP)=0
+        JDAHEP(2,NHEP)=0
+        CALL HWVEQU(5,PPAR,PHEP(1,NHEP))
+        CALL HWVEQU(4,VPAR(1,2),VHEP(1,NHEP))
+      ENDIF
+      KHEP=NHEP
+C---START WITH ANTICOLOUR DAUGHTER OF HARDEST PARTON
+      IPAR=2
+      JPAR=JCOPAR(4,IPAR)
+      NXPAR=NPAR/2
+      DO 20 IP=1,NXPAR
+      DO 10 JP=1,NXPAR
+      IF (JPAR.EQ.0) GOTO 15
+      IF (JCOPAR(2,JPAR).EQ.IPAR) THEN
+        IPAR=JPAR
+        JPAR=JCOPAR(4,IPAR)
+      ELSE
+        IPAR=JPAR
+        JPAR=JCOPAR(1,IPAR)
+      ENDIF
+   10 CONTINUE
+C---COULDN'T FIND COLOUR PARTNER
+      CALL HWWARN('HWBFIN',1,*999)
+   15 JPAR=JCOPAR(1,IPAR)
+      KHEP=KHEP+1
+      IF(KHEP.GT.NMXHEP) CALL HWWARN('HWBFIN',102,*999)
+      ID=IDPAR(IPAR)
+      IF (TMPAR(IPAR)) THEN
+        IF (ID.LT.14) THEN
+          ISTHEP(KHEP)=139
+        ELSEIF (ID.EQ.59) THEN
+          ISTHEP(KHEP)=139
+        ELSEIF (ID.LT.109) THEN
+          ISTHEP(KHEP)=130
+        ELSEIF (ID.LT.120) THEN
+          ISTHEP(KHEP)=139
+        ELSEIF (ABS(IDPDG(ID)).LT.1000000) THEN
+          ISTHEP(KHEP)=130
+        ELSEIF (ID.LT.425) THEN
+          ISTHEP(KHEP)=139
+        ELSEIF (ID.EQ.449) THEN
+          ISTHEP(KHEP)=139
+        ELSE
+          ISTHEP(KHEP)=130
+        ENDIF
+      ELSE
+        ISTHEP(KHEP)=ISTHEP(IHEP)+24
+      ENDIF
+      IDHW(KHEP)=ID
+      IDHEP(KHEP)=IDPDG(ID)
+      CALL HWVEQU(5,PPAR(1,IPAR),PHEP(1,KHEP))
+      CALL HWVEQU(4,VPAR(1,IPAR),VHEP(1,KHEP))
+      JMOHEP(1,KHEP)=IJET
+      JMOHEP(2,KHEP)=KHEP+1
+      JDAHEP(1,KHEP)=0
+      JDAHEP(2,KHEP)=KHEP-1
+   20 CONTINUE
+      JMOHEP(2,KHEP)=0
+      JDAHEP(2,NHEP+1)=0
+      JDAHEP(1,IJET)=NHEP+1
+      JDAHEP(2,IJET)=KHEP
+      NHEP=KHEP
+  999 END
+CDECK  ID>, HWBGEN.
+*CMZ :-        -14/10/99  18.04.56  by  Mike Seymour
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBGEN
+C-----------------------------------------------------------------------
+C     BRANCHING GENERATOR WITH INTERFERING GLUONS
+C     HWBGEN EVOLVES QCD JETS ACCORDING TO THE METHOD OF
+C     G.MARCHESINI & B.R.WEBBER, NUCL. PHYS. B238(1984)1
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWULDO,HWRGAU,EINHEP,ERTXI,RTXI,XF
+      INTEGER NTRY,LASHEP,IHEP,NRHEP,ID,IST,JHEP,KPAR,I,J,IRHEP(NMXJET),
+     & IRST(NMXJET)
+      LOGICAL HWRLOG
+      EXTERNAL HWULDO,HWRGAU
+      IF (IERROR.NE.0) RETURN
+      IF (IPRO.EQ.80) RETURN
+C---CHECK THAT EMSCA IS SET
+      IF (EMSCA.LE.ZERO) CALL HWWARN('HWBGEN',200,*999)
+      IF (HARDME) THEN
+C---FORCE A BRANCH INTO THE `DEAD ZONE' IN E+E-
+        IF (IPROC/10.EQ.10) CALL HWBDED(1)
+C---FORCE A BRANCH INTO THE `DEAD ZONE' IN DIS
+        IF (IPRO.EQ.90) CALL HWBDIS(1)
+C---FORCE A BRANCH INTO THE `DEAD ZONE' IN DRELL-YAN PROCESSES
+        IF (IPRO.EQ.13.OR.IPRO.EQ.14) CALL HWBDYP(1)
+C---FORCE A BRANCH INTO THE `DEAD ZONE' IN TOP DECAYS
+        CALL HWBTOP
+      ENDIF
+C---GENERATE INTRINSIC PT ONCE AND FOR ALL
+      DO 5 JNHAD=1,2
+        IF (PTRMS.NE.0.) THEN
+          PTINT(1,JNHAD)=HWRGAU(1,ZERO,PXRMS)
+          PTINT(2,JNHAD)=HWRGAU(2,ZERO,PXRMS)
+          PTINT(3,JNHAD)=PTINT(1,JNHAD)**2+PTINT(2,JNHAD)**2
+        ELSE
+          CALL HWVZRO(3,PTINT(1,JNHAD))
+        ENDIF
+ 5    CONTINUE
+      NTRY=0
+      LASHEP=NHEP
+ 10   NTRY=NTRY+1
+      IF (NTRY.GT.NETRY) CALL HWWARN('HWBGEN',ISLENT*100,*999)
+      NRHEP=0
+      NHEP=LASHEP
+      FROST=.FALSE.
+      DO 100 IHEP=1,LASHEP
+      IST=ISTHEP(IHEP)
+      IF (IST.GE.111.AND.IST.LE.115) THEN
+       NRHEP=NRHEP+1
+       IRHEP(NRHEP)=IHEP
+       IRST(NRHEP)=IST
+       ID=IDHW(IHEP)
+       IF (IST.NE.115) THEN
+C---FOUND A PARTON TO EVOLVE
+        NEVPAR=IHEP
+        NPAR=2
+        IDPAR(1)=17
+        IDPAR(2)=ID
+        TMPAR(1)=.TRUE.
+        PPAR(2,1)=0.
+        PPAR(4,1)=1.
+        DO 15 J=1,2
+        DO 15 I=1,2
+        JMOPAR(I,J)=0
+ 15     JCOPAR(I,J)=0
+C---SET UP EVOLUTION SCALE AND FRAME
+        JHEP=JMOHEP(2,IHEP)
+        IF (ID.EQ.13) THEN
+          IF (HWRLOG(HALF)) JHEP=JDAHEP(2,IHEP)
+        ELSEIF (IST.GT.112) THEN
+          IF ((ID.GT.6.AND.ID.LT.13).OR.
+     &        (ID.GT.214.AND.ID.LT.221)) JHEP=JDAHEP(2,IHEP)
+        ELSE
+          IF (ID.LT.7.OR.(ID.GT.208.AND.ID.LT.215)) JHEP=JDAHEP(2,IHEP)
+        ENDIF
+        IF (JHEP.LE.0.OR.JHEP.GT.NHEP) THEN
+          CALL HWWARN('HWBGEN',1,*999)
+          JHEP=IHEP
+        ENDIF
+        JCOPAR(1,1)=JHEP
+        EINHEP=PHEP(4,IHEP)
+        ERTXI=HWULDO(PHEP(1,IHEP),PHEP(1,JHEP))
+        IF (ERTXI.LT.ZERO) ERTXI=0.
+        IF (IST.LE.112.AND.IHEP.EQ.JHEP) ERTXI=0.
+        IF (ISTHEP(JHEP).EQ.155) THEN
+          ERTXI=ERTXI/PHEP(5,JHEP)
+          RTXI=1.
+        ELSE
+          ERTXI=SQRT(ERTXI)
+          RTXI=ERTXI/EINHEP
+        ENDIF
+        IF (RTXI.EQ.ZERO) THEN
+          XF=1.
+          PPAR(1,1)=0.
+          PPAR(3,1)=1.
+          PPAR(1,2)=EINHEP
+          PPAR(2,2)=0.
+          PPAR(4,2)=EINHEP
+        ELSE
+          XF=1./RTXI
+          PPAR(1,1)=1.
+          PPAR(3,1)=0.
+          PPAR(1,2)=ERTXI
+          PPAR(2,2)=1.
+          PPAR(4,2)=ERTXI
+        ENDIF
+        IF (PPAR(4,2).LT.PHEP(5,IHEP)) PPAR(4,2)=PHEP(5,IHEP)
+C---STORE MASS
+        PPAR(5,2)=PHEP(5,IHEP)
+        CALL HWVZRO(4,VPAR(1,1))
+        CALL HWVZRO(4,VPAR(1,2))
+        IF (IST.GT.112) THEN
+          TMPAR(2)=.TRUE.
+          INHAD=0
+          JNHAD=0
+          XFACT=0.
+        ELSE
+          TMPAR(2)=.FALSE.
+          JNHAD=IST-110
+          INHAD=JNHAD
+          IF (JDAHEP(1,JNHAD).NE.0) INHAD=JDAHEP(1,JNHAD)
+          XFACT=XF/PHEP(4,INHAD)
+          ANOMSC(1,JNHAD)=ZERO
+          ANOMSC(2,JNHAD)=ZERO
+        ENDIF
+C---FOR QUARKS IN A COLOUR SINGLET, ALLOW SOFT MATRIX-ELEMENT CORRECTION
+        HARDST=PPAR(4,2)
+        IF (SOFTME.AND.IDHW(IHEP).LT.13.AND.
+     $       ((JMOHEP(2,JHEP).EQ.IHEP.AND.JDAHEP(2,JHEP).EQ.IHEP).OR.
+     $       ISTHEP(JHEP).EQ.155)) HARDST=0
+C---CREATE BRANCHES AND COMPUTE ENERGIES
+        DO 20 KPAR=2,NMXPAR
+        IF (TMPAR(KPAR)) THEN
+          CALL HWBRAN(KPAR)
+        ELSE
+          CALL HWSBRN(KPAR)
+        ENDIF
+        IF (IERROR.NE.0) RETURN
+        IF (FROST) GOTO 100
+        IF (KPAR.EQ.NPAR) GOTO 30
+ 20     CONTINUE
+C---COMPUTE MASSES AND 3-MOMENTA
+ 30     CONTINUE
+        CALL HWBMAS
+        IF (AZSPIN) CALL HWBSPN
+        IF (TMPAR(2)) THEN
+           CALL HWBTIM(2,1)
+        ELSE
+           CALL HWBSPA
+        ENDIF
+C---ENTER PARTON JET IN /HEPEVT/
+        CALL HWBFIN(IHEP)
+       ELSE
+C---COPY SPECTATOR
+        NHEP=NHEP+1
+        IF (ID.GT.120.AND.ID.LT.133 .OR. ID.GE.198.AND.ID.LE.201) THEN
+          ISTHEP(NHEP)=190
+        ELSE
+          ISTHEP(NHEP)=152
+        ENDIF
+        IDHW(NHEP)=ID
+        IDHEP(NHEP)=IDPDG(ID)
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=0
+        JDAHEP(2,NHEP)=0
+        JDAHEP(1,IHEP)=NHEP
+        CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,NHEP))
+       ENDIF
+       ISTHEP(IHEP)=ISTHEP(IHEP)+10
+      ENDIF
+ 100  CONTINUE
+      IF (.NOT.FROST) THEN
+C---COMBINE JETS
+        ISTAT=20
+        CALL HWBJCO
+      ENDIF
+      IF (.NOT.FROST) THEN
+C---ATTACH SPECTATORS
+        ISTAT=30
+        CALL HWSSPC
+      ENDIF
+      IF (FROST) THEN
+C---BAD JET: RESTORE PARTONS AND RE-EVOLVE
+         DO 120 I=1,NRHEP
+ 120     ISTHEP(IRHEP(I))=IRST(I)
+         GOTO 10
+      ENDIF
+C---CONNECT COLOURS
+      CALL HWBCON
+      ISTAT=40
+      LASHEP=NHEP
+      IF (HARDME) THEN
+C---CLEAN UP IF THERE WAS A BRANCH IN THE `DEAD ZONE' IN E+E-
+        IF (IPROC/10.EQ.10) CALL HWBDED(2)
+C---CLEAN UP IF THERE WAS A BRANCH IN THE `DEAD ZONE' IN DIS
+        IF (IPRO.EQ.90) CALL HWBDIS(2)
+C---CLEAN UP IF THERE WAS A BRANCH IN THE `DEAD ZONE' IN DRELL-YAN PROC
+        IF (IPRO.EQ.13.OR.IPRO.EQ.14) CALL HWBDYP(2)
+      ENDIF
+C---IF THE CLEAN-UP OPERATION ADDED ANY PARTONS TO THE EVENT RECORD
+C   IT MIGHT NEED RESHOWERING
+      IF (NHEP.GT.LASHEP) THEN
+        LASHEP=NHEP
+        GOTO 10
+      ENDIF
+ 999  END
+CDECK  ID>, HWBJCO.
+*CMZ :-        -26/04/91  14.25.31  by  Federico Carminati
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBJCO
+C-----------------------------------------------------------------------
+C     COMBINES JETS WITH REQUIRED KINEMATICS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWULDO,EPS,PTX,PTY,PF,PTINF,PTCON,CN,CP,SP,PP0,
+     & PM0,ET0,DET,ECM,EMJ,EMP,EMS,DMS,ES,DPF,ALF,AL(2),ET(2),PP(2),
+     & PT(3),PB(5),PC(5),PQ(5),PR(5),PS(5),RR(3,3),RS(3,3),ETC,
+     & PJ(NMXJET),PM(NMXJET),PBR(5),RBR(3,3),DISP(4)
+      INTEGER LJET,IJ1,IST,IP,ICM,IP1,IP2,NP,IHEP,MHEP,JP,KP,LP,KHEP,
+     & JHEP,NE,IJT,IEND(2),IJET(NMXJET),IPAR(NMXJET)
+      LOGICAL AZCOR,JETRAD,DISPRO,DISLOW
+      EXTERNAL HWULDO
+      PARAMETER (EPS=1.D-4)
+      IF (IERROR.NE.0) RETURN
+      AZCOR=AZSOFT.OR.AZSPIN
+C---FIRST LOOK FOR SPACELIKE JETS
+      LJET=131
+  10  IJET(1)=1
+  20  IJ1=IJET(1)
+      DO 40 IHEP=IJ1,NHEP
+      IST=ISTHEP(IHEP)
+      IF (IST.EQ.137.OR.IST.EQ.138) IST=133
+      IF (IST.EQ.LJET) THEN
+C---FOUND AN UNBOOSTED JET - FIND PARTNERS
+        IP=JMOHEP(1,IHEP)
+        ICM=JMOHEP(1,IP)
+        DISPRO=IPRO/10.EQ.9.AND.IDHW(ICM).EQ.15
+        DISLOW=DISPRO.AND.JDAHEP(1,ICM).EQ.JDAHEP(2,ICM)-1
+        IF (IST.EQ.131) THEN
+          IP1=JMOHEP(1,ICM)
+          IP2=JMOHEP(2,ICM)
+        ELSE
+          IP1=JDAHEP(1,ICM)
+          IP2=JDAHEP(2,ICM)
+        ENDIF
+        IF (IP1.NE.IP) CALL HWWARN('HWBJCO',100,*999)
+        NP=0
+        DO 30 JHEP=IP1,IP2
+        NP=NP+1
+        IPAR(NP)=JHEP
+  30    IJET(NP)=JDAHEP(1,JHEP)
+        GOTO 50
+      ENDIF
+  40  CONTINUE
+C---NO MORE JETS?
+      IF (LJET.EQ.131) THEN
+        LJET=133
+        GOTO 10
+      ENDIF
+      RETURN
+  50  IF (LJET.EQ.131) THEN
+C---SPACELIKE JETS: FIND SPACELIKE PARTONS
+        IF (NP.NE.2) CALL HWWARN('HWBJCO',103,*999)
+C---special for DIS: FIND BOOST AND ROTATION FROM LAB TO BREIT FRAME
+        IF (DISPRO.AND.BREIT) THEN
+          IP=2
+          IF (JDAHEP(1,IP).NE.0) IP=JDAHEP(1,IP)
+          CALL HWVDIF(4,PHEP(1,JMOHEP(1,ICM)),PHEP(1,JDAHEP(1,ICM)),PB)
+          CALL HWUMAS(PB)
+C---IF Q**2<10**-2, SOMETHING MUST HAVE ALREADY GONE WRONG
+          IF (PB(5)**2.LT.1.D-2) CALL HWWARN('HWBJCO',102,*999)
+          CALL HWVSCA(4,PB(5)**2/HWULDO(PHEP(1,IP),PB),PHEP(1,IP),PBR)
+          CALL HWVSUM(4,PB,PBR,PBR)
+          CALL HWUMAS(PBR)
+          CALL HWULOF(PBR,PB,PB)
+          CALL HWUROT(PB,ONE,ZERO,RBR)
+        ENDIF
+        PTX=0.
+        PTY=0.
+        PF=1.D0
+        DO 90 IP=1,2
+        MHEP=IJET(IP)
+        IF (JDAHEP(1,MHEP).EQ.0) THEN
+C---SPECIAL FOR NON-PARTON JETS
+          IHEP=MHEP
+          GOTO 70
+        ELSE
+          IST=134+IP
+          DO 60 IHEP=MHEP,NHEP
+  60      IF (ISTHEP(IHEP).EQ.IST) GOTO 70
+C---COULDN'T FIND SPACELIKE PARTON
+          CALL HWWARN('HWBJCO',101,*999)
+        ENDIF
+  70    CALL HWVSCA(3,PF,PHEP(1,IHEP),PS)
+        IF (PTINT(3,IP).GT.ZERO) THEN
+C---ADD INTRINSIC PT
+          PT(1)=PTINT(1,IP)
+          PT(2)=PTINT(2,IP)
+          PT(3)=0.
+          CALL HWUROT(PS, ONE,ZERO,RS)
+          CALL HWUROB(RS,PT,PT)
+          CALL HWVSUM(3,PS,PT,PS)
+        ENDIF
+        JP=IJET(IP)+1
+        IF (AZCOR.AND.JP.LE.NHEP.AND.IDHW(JP).EQ.17) THEN
+C---ALIGN CONE WITH INTERFERING PARTON
+          CALL HWUROT(PS, ONE,ZERO,RS)
+          CALL HWUROF(RS,PHEP(1,JP),PR)
+          PTCON=PR(1)**2+PR(2)**2
+          KP=JMOHEP(2,JP)
+          IF (KP.EQ.0) THEN
+            CALL HWWARN('HWBJCO',1,*999)
+            PTINF=0.
+          ELSE
+            CALL HWVEQU(4,PHEP(1,KP),PB)
+            IF (DISPRO.AND.BREIT) THEN
+              CALL HWULOF(PBR,PB,PB)
+              CALL HWUROF(RBR,PB,PB)
+            ENDIF
+            PTINF=PB(1)**2+PB(2)**2
+            IF (PTINF.LT.EPS) THEN
+C---COLLINEAR JETS: ALIGN CONES
+              KP=JDAHEP(1,KP)+1
+              IF (ISTHEP(KP).EQ.100.AND.ISTHEP(KP-1)/10.EQ.14) THEN
+                CALL HWVEQU(4,PHEP(1,KP),PB)
+                IF (DISPRO.AND.BREIT) THEN
+                  CALL HWULOF(PBR,PB,PB)
+                  CALL HWUROF(RBR,PB,PB)
+                ENDIF
+                PTINF=PB(1)**2+PB(2)**2
+              ELSE
+                PTINF=0.
+              ENDIF
+            ENDIF
+          ENDIF
+          IF (PTCON.NE.ZERO.AND.PTINF.NE.ZERO) THEN
+            CN=1./SQRT(PTINF*PTCON)
+            CP=CN*(PR(1)*PB(1)+PR(2)*PB(2))
+            SP=CN*(PR(1)*PB(2)-PR(2)*PB(1))
+          ELSE
+            CALL HWRAZM( ONE,CP,SP)
+          ENDIF
+        ELSE
+          CALL HWRAZM( ONE,CP,SP)
+        ENDIF
+C---ROTATE SO SPACELIKE IS ALONG AXIS (APART FROM INTRINSIC PT)
+        CALL HWUROT(PS,CP,SP,RS)
+        IHEP=IJET(IP)
+        KHEP=JDAHEP(2,IHEP)
+        IF (KHEP.LT.IHEP) KHEP=IHEP
+        IEND(IP)=KHEP
+        DO 80 JHEP=IHEP,KHEP
+        CALL HWUROF(RS,PHEP(1,JHEP),PHEP(1,JHEP))
+  80    CALL HWUROF(RS,VHEP(1,JHEP),VHEP(1,JHEP))
+        PP(IP)=PHEP(4,IHEP)+PF*PHEP(3,IHEP)
+        ET(IP)=PHEP(1,IHEP)**2+PHEP(2,IHEP)**2-PHEP(5,IHEP)**2
+C---REDEFINE HARD CM
+        PTX=PTX+PHEP(1,IHEP)
+        PTY=PTY+PHEP(2,IHEP)
+  90    PF=-PF
+        PHEP(1,ICM)=PTX
+        PHEP(2,ICM)=PTY
+C---special for DIS: keep lepton momenta fixed
+        IF (DISPRO) THEN
+          IP1=JMOHEP(1,ICM)
+          IP2=JDAHEP(1,ICM)
+          IJT=IJET(1)
+C---IJT will be used to store lepton momentum transfer
+          CALL HWVDIF(4,PHEP(1,IP1),PHEP(1,IP2),PHEP(1,IJT))
+          CALL HWUMAS(PHEP(1,IJT))
+          IF (IDHEP(IP1).EQ.IDHEP(IP2)) THEN
+            IDHW(IJT)=200
+          ELSEIF (IDHEP(IP1).LT.IDHEP(IP2)) THEN
+            IDHW(IJT)=199
+          ELSE
+            IDHW(IJT)=198
+          ENDIF
+          IDHEP(IJT)=IDPDG(IDHW(IJT))
+          ISTHEP(IJT)=3
+C---calculate boost for struck parton
+C   PC is momentum of outgoing parton(s)
+          IP2=JDAHEP(2,ICM)
+          IF (.NOT.DISLOW) THEN
+C---FOR heavy QQbar PQ and PC are old and new QQbar momenta
+            CALL HWVSUM(4,PHEP(1,IP2-1),PHEP(1,IP2),PQ)
+            CALL HWUMAS(PQ)
+            PC(5)=PQ(5)
+          ELSE
+            PC(5)=PHEP(5,JDAHEP(1,IP2))
+          ENDIF
+          CALL HWVSUM(2,PHEP(1,IJT),PHEP(1,IJET(2)),PC)
+          ET(1)=ET(2)
+C---USE BREIT FRAME BOSON MOMENTUM IF NECESSARY
+          IF (BREIT) THEN
+            ET(2)=ET(1)+PC(5)**2+PHEP(5,IJET(2))**2
+            PM0=PHEP(5,IJT)
+            PP0=-PM0
+          ELSE
+            ET(2)=PC(1)**2+PC(2)**2+PC(5)**2
+            PP0=PHEP(4,IJT)+PHEP(3,IJT)
+            PM0=PHEP(4,IJT)-PHEP(3,IJT)
+          ENDIF
+          ET0=(PP0*PM0)+ET(1)-ET(2)
+          DET=ET0**2-4.*(PP0*PM0)*ET(1)
+          IF (DET.LT.ZERO) THEN
+            FROST=.TRUE.
+            RETURN
+          ENDIF
+          ALF=(SQRT(DET)-ET0)/(2.*PP0*PP(2))
+          PB(1)=0.
+          PB(2)=0.
+          PB(5)=2.D0
+          PB(3)=ALF-(1./ALF)
+          PB(4)=ALF+(1./ALF)
+          DO 100 IHEP=IJET(2),IEND(2)
+          CALL HWULOF(PB,PHEP(1,IHEP),PHEP(1,IHEP))
+          CALL HWULF4(PB,VHEP(1,IHEP),VHEP(1,IHEP))
+C---BOOST FROM BREIT FRAME IF NECESSARY
+          IF (BREIT) THEN
+            CALL HWUROB(RBR,PHEP(1,IHEP),PHEP(1,IHEP))
+            CALL HWULOB(PBR,PHEP(1,IHEP),PHEP(1,IHEP))
+            CALL HWUROB(RBR,VHEP(1,IHEP),VHEP(1,IHEP))
+            CALL HWULB4(PBR,VHEP(1,IHEP),VHEP(1,IHEP))
+          ENDIF
+  100     ISTHEP(IHEP)=ISTHEP(IHEP)+10
+          CALL HWVDIF(4,VHEP(1,IPAR(2)),VHEP(1,IJET(2)),DISP)
+          DO 110 IHEP=IJET(2),IEND(2)
+  110     CALL HWVSUM(4,DISP,VHEP(1,IHEP),VHEP(1,IHEP))
+          IF (IEND(2).GT.IJET(2)+1) ISTHEP(IJET(2)+1)=100
+          CALL HWVSUM(4,PHEP(1,IJT),PHEP(1,IJET(2)),PC)
+          CALL HWVSUM(4,PHEP(1,IP1),PHEP(1,IJET(2)),PHEP(1,ICM))
+          CALL HWUMAS(PHEP(1,ICM))
+        ELSEIF (IPRO/10.EQ.5) THEN
+C Special to preserve photon momentum
+           ETC=PTX**2+PTY**2+PHEP(5,ICM)**2
+           ET0=ETC+ET(1)-ET(2)
+           DET=ET0**2-4.*ETC*ET(1)
+           IF (DET.LT.ZERO) THEN
+              FROST=.TRUE.
+              RETURN
+           ENDIF
+           ALF=(SQRT(DET)+ET0-2.*ET(1))/(2.*PP(1)*PP(2))
+           PB(1)=0.
+           PB(2)=0.
+           PB(3)=ALF-1./ALF
+           PB(4)=ALF+1./ALF
+           PB(5)=2.
+           IJT=IJET(2)
+           DO 120 IHEP=IJT,IEND(2)
+           CALL HWULOF(PB,PHEP(1,IHEP),PHEP(1,IHEP))
+           CALL HWULF4(PB,VHEP(1,IHEP),VHEP(1,IHEP))
+  120      ISTHEP(IHEP)=ISTHEP(IHEP)+10
+           CALL HWVDIF(4,VHEP(1,IPAR(2)),VHEP(1,IJT),DISP)
+           DO 130 IHEP=IJT,IEND(2)
+  130      CALL HWVSUM(4,DISP,VHEP(1,IHEP),VHEP(1,IHEP))
+           IF (IEND(2).GT.IJT+1) ISTHEP(IJT+1)=100
+           ISTHEP(IJET(1))=ISTHEP(IJET(1))+10
+           CALL HWVSUM(2,PHEP(3,IPAR(1)),PHEP(3,IJT),PHEP(3,ICM))
+        ELSE
+          PHEP(4,ICM)=SQRT(PTX**2+PTY**2+PHEP(3,ICM)**2+PHEP(5,ICM)**2)
+C---NOW BOOST TO REQUIRED Q**2 AND X-F
+          PP0=PHEP(4,ICM)+PHEP(3,ICM)
+          PM0=PHEP(4,ICM)-PHEP(3,ICM)
+          ET0=(PP0*PM0)+ET(1)-ET(2)
+          DET=ET0**2-4.*(PP0*PM0)*ET(1)
+          IF (DET.LT.ZERO) THEN
+            FROST=.TRUE.
+            RETURN
+          ENDIF
+          DET=SQRT(DET)+ET0
+          AL(1)= 2.*PM0*PP(1)/DET
+          AL(2)=(PM0/PP(2))*(1.-2.*ET(1)/DET)
+          PB(1)=0.
+          PB(2)=0.
+          PB(5)=2.
+          DO 160 IP=1,2
+          PB(3)=AL(IP)-(1./AL(IP))
+          PB(4)=AL(IP)+(1./AL(IP))
+          IJT=IJET(IP)
+          DO 140 IHEP=IJT,IEND(IP)
+          CALL HWULOF(PB,PHEP(1,IHEP),PHEP(1,IHEP))
+          CALL HWULF4(PB,VHEP(1,IHEP),VHEP(1,IHEP))
+  140     ISTHEP(IHEP)=ISTHEP(IHEP)+10
+          CALL HWVDIF(4,VHEP(1,IPAR(IP)),VHEP(1,IJT),DISP)
+          DO 150 IHEP=IJT,IEND(IP)
+  150     CALL HWVSUM(4,DISP,VHEP(1,IHEP),VHEP(1,IHEP))
+          IF (IEND(IP).GT.IJT+1) THEN
+            ISTHEP(IJT+1)=100
+          ELSEIF (IEND(IP).EQ.IJT) THEN
+C---NON-PARTON JET
+            ISTHEP(IJT)=3
+          ENDIF
+  160     CONTINUE
+        ENDIF
+        ISTHEP(ICM)=120
+      ELSE
+C---TIMELIKE JETS
+C   special for DIS: preserve outgoing lepton momentum
+        IF (DISPRO) THEN
+          CALL HWVEQU(5,PHEP(1,IPAR(1)),PHEP(1,IJET(1)))
+          ISTHEP(IJET(1))=1
+          LP=2
+        ELSE
+          CALL HWVEQU(5,PHEP(1,ICM),PC)
+C--- PQ AND PC ARE OLD AND NEW PARTON CM
+          CALL HWVSUM(4,PHEP(1,IPAR(1)),PHEP(1,IPAR(2)),PQ)
+          PQ(5)=PHEP(5,ICM)
+          IF (NP.GT.2) THEN
+            DO 170 KP=3,NP
+  170       CALL HWVSUM(4,PHEP(1,IPAR(KP)),PQ,PQ)
+          ENDIF
+          LP=1
+        ENDIF
+        IF (.NOT.DISLOW) THEN
+C---FIND JET CM MOMENTA
+          ECM=PQ(5)
+          EMS=0.
+          JETRAD=.FALSE.
+          DO 180 KP=LP,NP
+          EMJ=PHEP(5,IJET(KP))
+          EMP=PHEP(5,IPAR(KP))
+          JETRAD=JETRAD.OR.EMJ.NE.EMP
+          EMS=EMS+EMJ
+          PM(KP)= EMJ**2
+C---N.B. ROUNDING ERRORS HERE AT HIGH ENERGIES
+          PJ(KP)=(HWULDO(PHEP(1,IPAR(KP)),PQ)/ECM)**2-EMP**2
+          IF (PJ(KP).LE.ZERO) CALL HWWARN('HWBJCO',104,*999)
+  180     CONTINUE
+          PF=1.
+          IF (JETRAD) THEN
+C---JETS DID RADIATE
+            IF (EMS.GE.ECM) THEN
+              FROST=.TRUE.
+              RETURN
+            ENDIF
+            DO 200 NE=1,NETRY
+            EMS=-ECM
+            DMS=0.
+            DO 190 KP=LP,NP
+            ES=SQRT(PF*PJ(KP)+PM(KP))
+            EMS=EMS+ES
+  190       DMS=DMS+PJ(KP)/ES
+            DPF=2.*EMS/DMS
+            IF (DPF.GT.PF) DPF=0.9*PF
+            PF=PF-DPF
+  200       IF (ABS(DPF).LT.EPS) GOTO 210
+            CALL HWWARN('HWBJCO',105,*999)
+          ENDIF
+  210     CONTINUE
+        ENDIF
+C---BOOST PC AND PQ TO BREIT FRAME IF NECESSARY
+        IF (DISPRO.AND.BREIT) THEN
+          CALL HWULOF(PBR,PC,PC)
+          CALL HWUROF(RBR,PC,PC)
+          IF (.NOT.DISLOW) THEN
+            CALL HWULOF(PBR,PQ,PQ)
+            CALL HWUROF(RBR,PQ,PQ)
+          ENDIF
+        ENDIF
+        DO 230 IP=LP,NP
+C---FIND CM ROTATION FOR JET IP
+        IF (.NOT.DISLOW) THEN
+          CALL HWVEQU(4,PHEP(1,IPAR(IP)),PR)
+          IF (DISPRO.AND.BREIT) THEN
+            CALL HWULOF(PBR,PR,PR)
+            CALL HWUROF(RBR,PR,PR)
+          ENDIF
+          CALL HWULOF(PQ,PR,PR)
+          CALL HWUROT(PR, ONE,ZERO,RR)
+          PR(1)=0.
+          PR(2)=0.
+          PR(3)=SQRT(PF*PJ(IP))
+          PR(4)=SQRT(PF*PJ(IP)+PM(IP))
+          PR(5)=PHEP(5,IJET(IP))
+          CALL HWUROB(RR,PR,PR)
+          CALL HWULOB(PC,PR,PR)
+        ELSE
+          CALL HWVEQU(5,PC,PR)
+        ENDIF
+C---NOW PR IS LAB/BREIT MOMENTUM OF JET IP
+        KP=IJET(IP)+1
+        IF (AZCOR.AND.KP.LE.NHEP.AND.IDHW(KP).EQ.17) THEN
+C---ALIGN CONE WITH INTERFERING PARTON
+          CALL HWUROT(PR, ONE,ZERO,RS)
+          JP=JMOHEP(2,KP)
+          IF (JP.EQ.0) THEN
+            CALL HWWARN('HWBJCO',2,*999)
+            PTINF=0.
+          ELSE
+            CALL HWVEQU(4,PHEP(1,JP),PS)
+            IF (DISPRO.AND.BREIT) THEN
+              CALL HWULOF(PBR,PS,PS)
+              CALL HWUROF(RBR,PS,PS)
+            ENDIF
+            CALL HWUROF(RS,PS,PS)
+            PTINF=PS(1)**2+PS(2)**2
+            IF (PTINF.LT.EPS) THEN
+C---COLLINEAR JETS: ALIGN CONES
+              JP=JDAHEP(1,JP)+1
+              IF (ISTHEP(JP).EQ.100.AND.ISTHEP(JP-1)/10.EQ.14) THEN
+                CALL HWVEQU(4,PHEP(1,JP),PS)
+                IF (DISPRO.AND.BREIT) THEN
+                  CALL HWULOF(PBR,PS,PS)
+                  CALL HWUROF(RBR,PS,PS)
+                ENDIF
+                CALL HWUROF(RS,PS,PS)
+                PTINF=PS(1)**2+PS(2)**2
+              ELSE
+                PTINF=0.
+              ENDIF
+            ENDIF
+          ENDIF
+          CALL HWVEQU(4,PHEP(1,KP),PB)
+          IF (DISPRO.AND.BREIT) THEN
+            CALL HWULOF(PBR,PB,PB)
+            CALL HWUROF(RBR,PB,PB)
+          ENDIF
+          PTCON=PB(1)**2+PB(2)**2
+          IF (PTCON.NE.ZERO.AND.PTINF.NE.ZERO) THEN
+            CN=1./SQRT(PTINF*PTCON)
+            CP=CN*(PS(1)*PB(1)+PS(2)*PB(2))
+            SP=CN*(PS(1)*PB(2)-PS(2)*PB(1))
+          ELSE
+            CALL HWRAZM( ONE,CP,SP)
+          ENDIF
+        ELSE
+          CALL HWRAZM( ONE,CP,SP)
+        ENDIF
+        CALL HWUROT(PR,CP,SP,RS)
+C---FIND BOOST FOR JET IP
+        ALF=(PHEP(3,IJET(IP))+PHEP(4,IJET(IP)))/
+     &      (PR(4)+SQRT((PR(4)+PR(5))*(PR(4)-PR(5))))
+        PB(1)=0.
+        PB(2)=0.
+        PB(3)=ALF-(1./ALF)
+        PB(4)=ALF+(1./ALF)
+        PB(5)=2.
+        IHEP=IJET(IP)
+        KHEP=JDAHEP(2,IHEP)
+        IF (KHEP.LT.IHEP) KHEP=IHEP
+        DO 220 JHEP=IHEP,KHEP
+        CALL HWULOF(PB,PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWUROB(RS,PHEP(1,JHEP),PHEP(1,JHEP))
+        CALL HWULF4(PB,VHEP(1,JHEP),VHEP(1,JHEP))
+        CALL HWUROB(RS,VHEP(1,JHEP),VHEP(1,JHEP))
+C---BOOST FROM BREIT FRAME IF NECESSARY
+        IF (DISPRO.AND.BREIT) THEN
+          CALL HWUROB(RBR,PHEP(1,JHEP),PHEP(1,JHEP))
+          CALL HWULOB(PBR,PHEP(1,JHEP),PHEP(1,JHEP))
+          CALL HWUROB(RBR,VHEP(1,JHEP),VHEP(1,JHEP))
+          CALL HWULB4(PBR,VHEP(1,JHEP),VHEP(1,JHEP))
+        ENDIF
+        CALL HWVSUM(4,VHEP(1,JHEP),VHEP(1,IPAR(IP)),VHEP(1,JHEP))
+  220   ISTHEP(JHEP)=ISTHEP(JHEP)+10
+        IF (KHEP.GT.IHEP+1) THEN
+          ISTHEP(IHEP+1)=100
+        ELSEIF (KHEP.EQ.IHEP) THEN
+C---NON-PARTON JET
+          ISTHEP(IHEP)=190
+        ENDIF
+  230   CONTINUE
+        IF (ISTHEP(ICM).EQ.110) ISTHEP(ICM)=120
+      ENDIF
+      GOTO 20
+  999 END
+CDECK  ID>, HWBMAS.
+*CMZ :-        -26/04/91  11.11.54  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBMAS
+C-----------------------------------------------------------------------
+C     Passes  backwards through a  jet cascade  calculating the masses
+C     and magnitudes of the longitudinal and transverse three momenta.
+C     Components given relative to direction of parent for a time-like
+C     vertex and with respect to z-axis for space-like vertices.
+C
+C     On input PPAR(1-5,*) contains:
+C     (E*sqrt(Xi),Xi,3-mom (if external),E,M-sq (if external))
+C
+C     On output PPAR(1-5,*) (if TMPAR(*)), containts:
+C     (P-trans,Xi or Xilast,P-long,E,M)
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWUSQR,EXI,PISQ,PJPK,EJEK,PTSQ,Z,ZMIN,ZMAX,
+     $     EMI,EMJ,EMK,C,NQ,HWBVMC,RHO,POLD,PNEW,EOLD,ENEW,A,B
+      INTEGER IPAR,JPAR,KPAR,MPAR,I,J,K
+      EXTERNAL HWUSQR
+      IF (IERROR.NE.0) RETURN
+      IF (NPAR.GT.2) THEN
+        DO 30 MPAR=NPAR-1,3,-2
+         JPAR=MPAR
+C Find parent and partner of this branch
+         IPAR=JMOPAR(1,JPAR)
+         KPAR=JPAR+1
+C Determine type of branching
+         IF (TMPAR(IPAR)) THEN
+C Time-like branching
+C           Compute mass of parent
+            EXI=PPAR(1,JPAR)*PPAR(1,KPAR)
+            PPAR(5,IPAR)=PPAR(5,JPAR)+PPAR(5,KPAR)+2.*EXI
+C           Compute three momentum of parent
+            PISQ=PPAR(4,IPAR)*PPAR(4,IPAR)-PPAR(5,IPAR)
+            PPAR(3,IPAR)=HWUSQR(PISQ)
+C---SPECIAL FOR G-->QQBAR: READJUST ANGULAR DISTRIBUTION
+            IF (IDPAR(IPAR).EQ.13 .AND. IDPAR(JPAR).LT.13) THEN
+              Z=PPAR(4,JPAR)/PPAR(4,IPAR)
+              ZMIN=HWBVMC(IDPAR(JPAR))/PPAR(1,JPAR)*Z
+              RHO=(Z*(3-Z*(3-2*Z))-ZMIN*(3-ZMIN*(3-2*ZMIN)))
+     $             /(2*(1-2*ZMIN)*(1-ZMIN*(1-ZMIN)))
+              NQ=PPAR(3,IPAR)*(PPAR(3,IPAR)+PPAR(4,IPAR))
+              EMI=PPAR(5,IPAR)
+              EMJ=PPAR(5,JPAR)
+              EMK=PPAR(5,KPAR)
+              ZMIN=MAX((EMI+EMJ-EMK)/(2*(EMI+NQ)),
+     $           (EMI+EMJ-EMK-SQRT((EMI-EMJ-EMK)**2-4*EMJ*EMK))/(2*EMI))
+              ZMAX=1-MAX((EMI-EMJ+EMK)/(2*(EMI+NQ)),
+     $           (EMI-EMJ+EMK-SQRT((EMI-EMJ-EMK)**2-4*EMJ*EMK))/(2*EMI))
+              C=2*RMASS(IDPAR(JPAR))**2/EMI
+              Z=(4*ZMIN*(1.5*(1+C-ZMIN)+ZMIN**2)*(1-RHO)
+     $          +4*ZMAX*(1.5*(1+C-ZMAX)+ZMAX**2)*RHO-2-3*C)/(1+2*C)**1.5
+              Z=SQRT(1+2*C)*SINH(LOG(Z+SQRT(Z**2+1))/3)+0.5
+              Z=(Z*NQ+(EMI+EMJ-EMK)/2)/(NQ+EMI)
+              PPAR(4,JPAR)=Z*PPAR(4,IPAR)
+              PPAR(4,KPAR)=PPAR(4,IPAR)-PPAR(4,JPAR)
+              PPAR(3,JPAR)=HWUSQR(PPAR(4,JPAR)**2-EMJ)
+              PPAR(3,KPAR)=HWUSQR(PPAR(4,KPAR)**2-EMK)
+              PPAR(2,JPAR)=EXI/(PPAR(4,JPAR)*PPAR(4,KPAR))
+              IF(JDAPAR(2,JPAR).NE.0)PPAR(2,JDAPAR(2,JPAR))=PPAR(2,JPAR)
+              IF(JDAPAR(2,KPAR).NE.0)PPAR(2,JDAPAR(2,KPAR))=PPAR(2,JPAR)
+C---FIND DESCENDENTS OF THIS SPLITTING AND READJUST THEIR MOMENTA TOO
+              DO 20 J=JPAR+2,NPAR-1,2
+                I=J
+ 10             I=JMOPAR(1,I)
+                IF (I.GT.IPAR) GOTO 10
+                IF (I.EQ.IPAR) THEN
+                  I=JMOPAR(1,J)
+                  K=J+1
+                  POLD=PPAR(3,J)+PPAR(3,K)
+                  EOLD=PPAR(4,J)+PPAR(4,K)
+                  PNEW=HWUSQR(PPAR(4,I)**2-PPAR(5,I))
+                  ENEW=PPAR(4,I)
+                  A=(ENEW*EOLD-PNEW*POLD)/PPAR(5,I)
+                  B=(PNEW*EOLD-ENEW*POLD)/PPAR(5,I)
+                  PPAR(3,J)=A*PPAR(3,J)+B*PPAR(4,J)
+                  PPAR(4,J)=(PPAR(4,J)+B*PPAR(3,J))/A
+                  PPAR(3,K)=PNEW-PPAR(3,J)
+                  PPAR(4,K)=ENEW-PPAR(4,J)
+                  PPAR(2,J)=1-(PPAR(3,J)*PPAR(3,K)+PPAR(1,J)*PPAR(1,K))
+     $                 /(PPAR(4,J)*PPAR(4,K))
+                  IF (JDAPAR(2,J).NE.0) PPAR(2,JDAPAR(2,J))=PPAR(2,J)
+                  IF (JDAPAR(2,K).NE.0) PPAR(2,JDAPAR(2,K))=PPAR(2,J)
+                ENDIF
+ 20           CONTINUE
+            ENDIF
+C           Compute daughter' transverse and longitudinal momenta
+            PJPK=PPAR(3,JPAR)*PPAR(3,KPAR)
+            EJEK=PPAR(4,JPAR)*PPAR(4,KPAR)-EXI
+            PTSQ=(PJPK+EJEK)*(PJPK-EJEK)/PISQ
+            PPAR(1,JPAR)=HWUSQR(PTSQ)
+            PPAR(3,JPAR)=HWUSQR(PPAR(3,JPAR)*PPAR(3,JPAR)-PTSQ)
+            PPAR(1,KPAR)=-PPAR(1,JPAR)
+            PPAR(3,KPAR)= PPAR(3,IPAR)-PPAR(3,JPAR)
+         ELSE
+C Space-like branching
+C           Re-arrange such that JPAR is time-like
+            IF (TMPAR(KPAR)) THEN
+               KPAR=JPAR
+               JPAR=JPAR+1
+            ENDIF
+C           Compute time-like branch
+            PTSQ=(2.-PPAR(2,JPAR))*PPAR(1,JPAR)*PPAR(1,JPAR)
+     &          -PPAR(5,JPAR)
+            PPAR(1,JPAR)=HWUSQR(PTSQ)
+            PPAR(3,JPAR)=(1.-PPAR(2,JPAR))*PPAR(4,JPAR)
+            PPAR(3,IPAR)=PPAR(3,KPAR)-PPAR(3,JPAR)
+            PPAR(5,IPAR)=0.
+            PPAR(1,KPAR)=0.
+         ENDIF
+C Reset Xi to Xilast
+         PPAR(2,KPAR)=PPAR(2,IPAR)
+ 30    CONTINUE
+      ENDIF
+      DO 40 IPAR=2,NPAR
+ 40   PPAR(5,IPAR)=HWUSQR(PPAR(5,IPAR))
+      PPAR(1,2)=0.
+      PPAR(2,2)=0.
+      END
+CDECK  ID>, HWBRAN.
+*CMZ :-        -14/10/99  18.04.56  by  Mike Seymour
+*-- Author :    Bryan Webber & Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBRAN(KPAR)
+C-----------------------------------------------------------------------
+C     BRANCHES TIMELIKE PARTON KPAR INTO TWO, PUTS PRODUCTS
+C     INTO NPAR+1 AND NPAR+2, AND INCREASES NPAR BY TWO
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBVMC,HWR,HWUALF,HWUTAB,HWRUNI,HWULDO,PMOM,
+     & QNOW,QLST,QKTHR,RN,QQBAR,DQQ,QGTHR,SNOW,QSUD,ZMIN,ZMAX,ZRAT,WMIN,
+     & QLAM,Z1,Z2,ETEST,ZTEST,ENOW,XI,XIPREV,EPREV,QMAX,QGAM,SLST,SFNL,
+     & TARG,ALF,BETA0(3:6),BETAP(3:6),SQRK(4:6,5),REJFAC,Z,X1,X2,OTHXI,
+     & OTHZ,X3,FF,AW,XCUT,CC,JJ,HWUSQR
+      INTEGER HWRINT,KPAR,ID,JD,IS,NTRY,N,ID1,ID2,MPAR,ISUD(13),IHEP,
+     & JHEP,M,NF,NN,IREJ,NREJ,ITOP
+      EXTERNAL HWBVMC,HWR,HWUALF,HWUTAB,HWRUNI,HWULDO,HWRINT,HWUSQR
+      SAVE BETA0,BETAP,SQRK
+      DATA ISUD,BETA0/2,2,3,4,5,6,2,2,3,4,5,6,1,4*ZERO/
+      IF (IERROR.NE.0) RETURN
+C---SET SQRK(M,N) TO THE PROBABILITY THAT A GLUON WILL NOT PRODUCE A
+C   QUARK-ANTIQUARK PAIR BETWEEN SCALES RMASS(M) AND 2*HWBVMC(N)
+      IF (SUDORD.NE.1.AND.BETA0(3).EQ.ZERO) THEN
+        DO 100 M=3,6
+          BETA0(M)=(11.*CAFAC-2.*M)*0.5
+ 100      BETAP(M)=(17.*CAFAC**2-(5.*CAFAC+3.*CFFAC)*M)
+     &            /BETA0(M)*0.25/PIFAC
+        DO 120 N=1,5
+          DO 110 M=4,6
+            IF (M.LE.N) THEN
+              SQRK(M,N)=ONE
+            ELSEIF (M.EQ.4.OR.M.EQ.N+1) THEN
+              NF=M
+              IF (2*HWBVMC(N).GT.RMASS(M)) NF=M+1
+              SQRK(M,N)=((BETAP(NF-1)+1/HWUALF(1,2*HWBVMC(N)))/
+     $             (BETAP(NF-1)+1/HWUALF(1,RMASS(M))))**(1/BETA0(NF-1))
+            ELSE
+              SQRK(M,N)=SQRK(M-1,N)*
+     $             ((BETAP(M-1)+1/HWUALF(1,RMASS(M-1)))/
+     $             (BETAP(M-1)+1/HWUALF(1,RMASS(M))))**(1/BETA0(M-1))
+            ENDIF
+ 110      CONTINUE
+ 120    CONTINUE
+      ENDIF
+      ID=IDPAR(KPAR)
+C--TEST FOR PARTON TYPE
+      IF (ID.LE.13) THEN
+        JD=ID
+        IS=ISUD(ID)
+      ELSEIF (ID.GE.209.AND.ID.LE.220) THEN
+        JD=ID-208
+        IS=7
+      ELSE
+        IS=0
+      END IF
+      QNOW=-1.
+      IF (IS.NE.0) THEN
+C--TIMELIKE PARTON BRANCHING
+        ENOW=PPAR(4,KPAR)
+        XIPREV=PPAR(2,KPAR)
+        IF (JMOPAR(1,KPAR).EQ.0) THEN
+          EPREV=PPAR(4,KPAR)
+        ELSE
+          EPREV=PPAR(4,JMOPAR(1,KPAR))
+        ENDIF
+C--IF THIS IS CHARGED & PHOTONS ARE ALLOWED, ANGLES MIGHT NOT BE ORDERED
+        QMAX=0
+        QLST=PPAR(1,KPAR)
+        IF (ICHRG(ID).NE.0 .AND. VPCUT.LT.PPAR(1,2)) THEN
+C--LOOK FOR A PREVIOUS G->QQBAR, IF ANY
+          MPAR=KPAR
+ 1        IF (JMOPAR(1,MPAR).NE.0) THEN
+            IF (IDPAR(JMOPAR(1,MPAR)).EQ.ID) THEN
+              MPAR=JMOPAR(1,MPAR)
+              GOTO 1
+            ENDIF
+          ENDIF
+C--IF CLIMBED TO THE TOP OF THE LIST, FIND QED INTERFERENCE PARTNER
+          IF (MPAR.EQ.2) THEN
+            JHEP=0
+            IF (ID.LT.7) THEN
+              IHEP=JDAHEP(2,JCOPAR(1,1))
+              IF (IHEP.GT.0) JHEP=JDAHEP(2,IHEP)
+            ELSE
+              IHEP=JMOHEP(2,JCOPAR(1,1))
+              IF (IHEP.GT.0) JHEP=JMOHEP(2,IHEP)
+            ENDIF
+            IF (IHEP.GT.0.AND.JHEP.GT.0) THEN
+               QMAX=HWULDO(PHEP(1,IHEP),PHEP(1,JHEP))
+     &              *(ENOW/PPAR(4,2))**2
+            ELSE
+C--FIX AT HARD PROCESS SCALE IF POINTER NOT YET SET
+C  (CAN HAPPEN IN SUSY EVENTS)
+               QMAX=EMSCA**2
+            ENDIF
+          ELSE
+            QMAX=ENOW**2*PPAR(2,MPAR)
+          ENDIF
+C--IF PREVIOUS BRANCHING WAS Q->QGAMMA, LOOK FOR A QCD BRANCHING
+          MPAR=KPAR
+ 2        IF (JMOPAR(1,MPAR).NE.0) THEN
+            IF (IDPAR(JDAPAR(1,JMOPAR(1,MPAR))).EQ.59 .OR.
+     &        IDPAR(JDAPAR(2,JMOPAR(1,MPAR))).EQ.59) THEN
+              MPAR=JMOPAR(1,MPAR)
+              GOTO 2
+            ENDIF
+          ENDIF
+          QLST=ENOW**2*PPAR(2,MPAR)
+          QMAX=SQRT(MAX(ZERO,MIN(
+     &         QMAX , EPREV**2*XIPREV , ENOW**2*XIPREV*(2-XIPREV))))
+          QLST=SQRT(MIN(
+     &         QLST , EPREV**2*XIPREV , ENOW**2*XIPREV*(2-XIPREV)))
+        ENDIF
+        NTRY=0
+    5   NTRY=NTRY+1
+        IF (NTRY.GT.NBTRY) CALL HWWARN('HWBRAN',100,*999)
+        IF (ID.EQ.13) THEN
+C--GLUON -> QUARK+ANTIQUARK OPTION
+          IF (QLST.GT.QCDL3) THEN
+            DO 8 N=1,NFLAV
+            QKTHR=2.*HWBVMC(N)
+            IF (QLST.GT.QKTHR) THEN
+              RN=HWR()
+              IF (SUDORD.NE.1) THEN
+C---FIND IN WHICH FLAVOUR INTERVAL THE UPPER LIMIT LIES
+                NF=3
+                DO 200 M=MAX(3,N),NFLAV
+ 200              IF (QLST.GT.RMASS(M)) NF=M
+C---CALCULATE THE FORM FACTOR
+                IF (NF.EQ.MAX(3,N)) THEN
+                  SFNL=((BETAP(NF)+1/HWUALF(1,QKTHR))/
+     $                 (BETAP(NF)+1/HWUALF(1,QLST)))**(1/BETA0(NF))
+                  SLST=SFNL
+                ELSE
+                  SFNL=((BETAP(NF)+1/HWUALF(1,RMASS(NF)))/
+     $                 (BETAP(NF)+1/HWUALF(1,QLST)))**(1/BETA0(NF))
+                  SLST=SFNL*SQRK(NF,N)
+                ENDIF
+              ENDIF
+              IF (RN.GT.1.E-3) THEN
+                QQBAR=QCDL3*(QLST/QCDL3)**(RN**BETAF)
+              ELSE
+                QQBAR=QCDL3
+              ENDIF
+              IF (SUDORD.NE.1) THEN
+C---FIND IN WHICH FLAVOUR INTERVAL THE SOLUTION LIES
+                IF (RN.GE.SFNL) THEN
+                  NN=NF
+                ELSEIF (RN.GE.SLST) THEN
+                  NN=MAX(3,N)
+                  DO 210 M=MAX(3,N)+1,NF-1
+ 210                IF (RN.GE.SLST/SQRK(M,N)) NN=M
+                ELSE
+                  NN=0
+                  QQBAR=QCDL3
+                ENDIF
+                IF (NN.GT.0) THEN
+                  IF (NN.EQ.NF) THEN
+                    TARG=HWUALF(1,QLST)
+                  ELSE
+                    TARG=HWUALF(1,RMASS(NN+1))
+                    RN=RN/SLST*SQRK(NN+1,N)
+                  ENDIF
+                  TARG=1/((BETAP(NN)+1/TARG)*RN**BETA0(NN)-BETAP(NN))
+C---NOW SOLVE HWUALF(1,QQBAR)=TARG FOR QQBAR ITERATIVELY
+ 7                QQBAR=MAX(QQBAR,HALF*QKTHR)
+                  ALF=HWUALF(1,QQBAR)
+                  IF (ABS(ALF-TARG).GT.ACCUR) THEN
+                    NTRY=NTRY+1
+                    IF (NTRY.GT.NBTRY) CALL HWWARN('HWBRAN',101,*999)
+                    QQBAR=QQBAR*(1+3*PIFAC*(ALF-TARG)
+     $                   /(BETA0(NN)*ALF**2*(1+BETAP(NN)*ALF)))
+                    GOTO 7
+                  ENDIF
+                ENDIF
+              ENDIF
+              IF (QQBAR.GT.QNOW.AND.QQBAR.GT.QKTHR) THEN
+                QNOW=QQBAR
+                ID2=N
+              ENDIF
+            ELSE
+              GOTO 9
+            ENDIF
+    8       CONTINUE
+          ENDIF
+C--GLUON->DIQUARKS OPTION
+    9     IF (QLST.LT.QDIQK) THEN
+            IF (PDIQK.NE.ZERO) THEN
+              RN=HWR()
+              DQQ=QLST*EXP(-RN/PDIQK)
+              IF (DQQ.GT.QNOW) THEN
+                IF (DQQ.GT.2.*RMASS(115)) THEN
+                  QNOW=DQQ
+                  ID2=115
+                ENDIF
+              ENDIF
+            ENDIF
+          ENDIF
+        ENDIF
+C--ENHANCE GLUON AND PHOTON EMISSION BY A FACTOR OF TWO IF THIS BRANCH
+C  IS CAPABLE OF BEING THE HARDEST SO FAR
+        NREJ=1
+        IF (TMPAR(2).AND.0.25*MAX(QLST,QMAX).GT.HARDST) NREJ=2
+C--BRANCHING ID->ID+GLUON
+        QGTHR=HWBVMC(ID)+HWBVMC(13)
+        IF (QLST.GT.QGTHR) THEN
+         DO 300 IREJ=1,NREJ
+          RN=HWR()
+          SLST=HWUTAB(SUD(1,IS),QEV(1,IS),NQEV,QLST,INTER)
+          IF (RN.EQ.ZERO) THEN
+            SNOW=2.
+          ELSE
+            SNOW=SLST/RN
+          ENDIF
+          IF (SNOW.LT.ONE) THEN
+            QSUD=HWUTAB(QEV(1,IS),SUD(1,IS),NQEV,SNOW,INTER)
+C---IF FORM FACTOR DID NOT GET INVERTED CORRECTLY TRY LINEAR INSTEAD
+            IF (QSUD.GT.QLST) THEN
+              SNOW=HWUTAB(SUD(1,IS),QEV(1,IS),NQEV,QLST,1)/RN
+              QSUD=HWUTAB(QEV(1,IS),SUD(1,IS),NQEV,SNOW,1)
+              IF (QSUD.GT.QLST) THEN
+                CALL HWWARN('HWBRAN',1,*999)
+                QSUD=-1
+              ENDIF
+            ENDIF
+            IF (QSUD.GT.QGTHR.AND.QSUD.GT.QNOW) THEN
+              ID2=13
+              QNOW=QSUD
+            ENDIF
+          ENDIF
+ 300     CONTINUE
+        ENDIF
+C--BRANCHING ID->ID+PHOTON
+        IF (ICHRG(ID).NE.0) THEN
+          QGTHR=MAX(HWBVMC(ID)+HWBVMC(59),HWBVMC(59)*EXP(0.75))
+          IF (QMAX.GT.QGTHR) THEN
+           DO 400 IREJ=1,NREJ
+            RN=HWR()
+            IF (RN.EQ.ZERO) THEN
+              QGAM=0
+            ELSE
+              QGAM=(LOG(QMAX/HWBVMC(59))-0.75)**2
+     &            +PIFAC*9/(ICHRG(ID)**2*ALPFAC*ALPHEM)*LOG(RN)
+              IF (QGAM.GT.ZERO) THEN
+                QGAM=HWBVMC(59)*EXP(0.75+SQRT(QGAM))
+              ELSE
+                QGAM=0
+              ENDIF
+            ENDIF
+            IF (QGAM.GT.QGTHR.AND.QGAM.GT.QNOW) THEN
+              ID2=59
+              QNOW=QGAM
+            ENDIF
+ 400       CONTINUE
+          ENDIF
+        ENDIF
+        IF (QNOW.GT.ZERO) THEN
+C--BRANCHING HAS OCCURRED
+          ZMIN=HWBVMC(ID2)/QNOW
+          ZMAX=1.-ZMIN
+          IF (ID.EQ.13) THEN
+            IF (ID2.EQ.13) THEN
+C--GLUON -> GLUON + GLUON
+              ID1=13
+              WMIN=ZMIN*ZMAX
+              ETEST=(1.-WMIN)**2*HWUALF(5-SUDORD*2,QNOW*WMIN)
+              ZRAT=(ZMAX*(1-ZMIN))/(ZMIN*(1-ZMAX))
+C--CHOOSE Z1 DISTRIBUTED ON (ZMIN,ZMAX)
+C  ACCORDING TO GLUON BRANCHING FUNCTION
+   10         Z1=ZMAX/(ZMAX+(1-ZMAX)*ZRAT**HWR())
+              Z2=1.-Z1
+              ZTEST=(1.-(Z1*Z2))**2*HWUALF(5-SUDORD*2,QNOW*(Z1*Z2))
+              IF (ZTEST.LT.ETEST*HWR()) GOTO 10
+              Z=Z1
+            ELSEIF (ID2.NE.115) THEN
+C--GLUON -> QUARKS
+              ID1=ID2+6
+              ETEST=ZMIN**2+ZMAX**2
+   20         Z1=HWRUNI(0,ZMIN,ZMAX)
+              Z2=1.-Z1
+              ZTEST=Z1*Z1+Z2*Z2
+              IF (ZTEST.LT.ETEST*HWR()) GOTO 20
+            ELSE
+C--GLUON -> DIQUARKS
+              ID2=HWRINT(115,117)
+              ID1=ID2-6
+              Z1=HWRUNI(0,ZMIN,ZMAX)
+              Z2=1.-Z1
+            ENDIF
+          ELSE
+C--QUARK OR ANTIQUARK BRANCHING
+            IF (ID2.EQ.13) THEN
+C--TO GLUON
+              ZMAX=1.-HWBVMC(ID)/QNOW
+              WMIN=MIN(ZMIN*(1.-ZMIN),ZMAX*(1.-ZMAX))
+              ETEST=(1.+ZMAX**2)*HWUALF(5-SUDORD*2,QNOW*WMIN)
+              ZRAT=ZMAX/ZMIN
+   30         Z1=ZMIN*ZRAT**HWR()
+              Z2=1.-Z1
+              ZTEST=(1.+Z2*Z2)*HWUALF(5-SUDORD*2,QNOW*Z1*Z2)
+              IF (ZTEST.LT.ETEST*HWR()) GOTO 30
+            ELSE
+C--TO PHOTON
+              ZMIN=  HWBVMC(59)/QNOW
+              ZMAX=1-HWBVMC(ID)/QNOW
+              ZRAT=ZMAX/ZMIN
+              ETEST=1+(1-ZMIN)**2
+   40         Z1=ZMIN*ZRAT**HWR()
+              Z2=1-Z1
+              ZTEST=1+Z2*Z2
+              IF (ZTEST.LT.ETEST*HWR()) GOTO 40
+            ENDIF
+C--QUARKS EMIT ON LOWER SIDE, ANTIQUARKS ON UPPER SIDE
+            Z=Z1
+            IF (JD.LE.6) THEN
+              Z1=Z2
+              Z2=1.-Z2
+              ID1=ID
+            ELSE
+              ID1=ID2
+              ID2=ID
+            ENDIF
+          ENDIF
+C--UPDATE THIS BRANCH AND CREATE NEW BRANCHES
+          XI=(QNOW/ENOW)**2
+          IF (ID1.NE.59.AND.ID2.NE.59) THEN
+            IF (ID.EQ.13.AND.ID1.NE.13) THEN
+              QLAM=QNOW
+            ELSE
+              QLAM=QNOW*Z1*Z2
+            ENDIF
+            IF (SUDORD.EQ.1.AND.HWUALF(2,QLAM).LT.HWR() .OR.
+     &           (2.-XI)*(QNOW*Z1*Z2)**2.GT.EMSCA**2) THEN
+C--BRANCHING REJECTED: REDUCE Q AND REPEAT
+                QMAX=QNOW
+                QLST=QNOW
+                QNOW=-1.
+                GOTO 5
+            ENDIF
+          ENDIF
+C--IF THIS IS HARDEST EMISSION SO FAR, APPLY MATRIX-ELEMENT CORRECTION
+          IF (ID.NE.13.OR.ID1.EQ.13) THEN
+            QLAM=QNOW*Z1*Z2
+            REJFAC=1
+            IF (TMPAR(2).AND.QLAM.GT.HARDST) THEN
+C----SOFT MATRIX-ELEMENT CORRECTION TO TOP DECAYS
+              ITOP=JCOPAR(1,1)
+              IF (ISTHEP(ITOP).EQ.155.AND.(IDHW(ITOP).EQ.6
+     $             .OR.IDHW(ITOP).EQ.12)) THEN
+                AW=(PHEP(5,JDAHEP(1,ITOP))/PHEP(5,ITOP))**2
+                FF=0.5*(1-AW)*(1-2*AW+1/AW)
+                CC=0.25*(1-AW)**2
+                X1=1-2*CC*Z*(1-Z)*XI
+                X3=0.5*(1-AW+2*CC*Z*(1-Z)*XI-(1-2*Z)
+     &               *HWUSQR(((1+AW-2*CC*Z*(1-Z)*XI)**2-4*AW)
+     &               /(1-2*Z*(1-Z)*XI)))
+C-----JACOBIAN FACTOR
+                JJ=(1-X1)*(2-AW-X1-2*X3)*(1-2*Z*(1-Z)*XI)/(
+     $               4*CC**2*((X1+AW)**2-4*AW)*Z**2*(1-Z)**2*(1-2*Z)*XI)
+C-----REJECTION FACTOR
+                XCUT=2*GCUTME/PHEP(5,ITOP)
+                IF (X3.GT.XCUT) REJFAC=FF*JJ
+     &               *X3**2*(1-X1)*(1+(1-Z)**2)/(Z*XI)
+     &               /((1+1/AW-2*AW)*((1-AW)*X3-(1-X1)
+     &               *(1-X3)-X3**2)+(1+1/(2*AW))*X3*(X1+X3-1)**2
+     &               +2*X3**2*(1-X1))
+              ELSEIF (MOD(ISTHEP(JCOPAR(1,1)),10).GE.3) THEN
+C---COLOUR PARTNER IS ALSO OUTGOING
+                X1=1-Z*(1-Z)*XI
+                X2=0.5*(1+Z*(1-Z)*XI +
+     $               (1-Z*(1-Z)*XI)*(1-2*Z)/SQRT(1-2*Z*(1-Z)*XI))
+                REJFAC=SQRT(2*X1-1)/(X1*Z*(1-Z))
+     $               *(1+(1-Z)**2)/(Z*XI)
+     $               *(1-X1)*(1-X2)/(X1**2+X2**2)
+C---CHECK WHETHER IT IS IN THE OVERLAP REGION
+                OTHXI=4*(1-X2)*X2**2/(X2**2-(2*X2-1)*(2*X1+X2-2)**2)
+                IF (OTHXI.LT.ONE) THEN
+                  OTHZ=0.5*(1-SQRT(2*X2-1)/X2*(2*X1+X2-2))
+                  REJFAC=REJFAC+SQRT(2*X2-1)/(X2*OTHZ*(1-OTHZ))
+     $                 *(1+(1-OTHZ)**2)/(OTHZ*OTHXI)
+     $                 *(1-X2)*(1-X1)/(X2**2+X1**2)
+                ENDIF
+              ELSE
+C---COLOUR PARTNER IS INCOMING (X1=XP, X2=ZP)
+                X1=1/(1+Z*(1-Z)*XI)
+                X2=0.5*(1+(1-2*Z)/SQRT(1-2*Z*(1-Z)*XI))
+                REJFAC=SQRT(3-2/X1)/(X1**2*Z*(1-Z))
+     $               *(1+(1-Z)**2)/(Z*XI)
+     $               *(1-X1)*(1-X2)/
+     $               (1+(1-X1-X2+2*X1*X2)**2+2*(1-X1)*(1-X2)*X1*X2)
+C---CHECK WHETHER IT IS IN THE OVERLAP REGION
+                OTHXI=(SQRT(X1+2*(1-X2)*(1-X2+X1*X2))-SQRT(X1))**2/
+     $               (1+X1-X2-SQRT(X1*(X1+2*(1-X2)*(1-X2+X1*X2))))
+                OTHZ=(SQRT(X1*(X1+2*(1-X2)*(1-X2+X1*X2)))-X1)/(1-X2)
+                IF (OTHXI.LT.OTHZ**2) THEN
+                  REJFAC=REJFAC+OTHZ**3*(1-X1-X2+2*X1*X2)
+     $                 /(X1**2*(1-OTHZ)*(OTHZ+OTHXI*(1-OTHZ)))
+     $                 *(1+OTHZ**2)/((1-OTHZ)*OTHXI)
+     $                 *(1-X1)*(1-X2)/
+     $                 (1+(1-X1-X2+2*X1*X2)**2+2*(1-X1)*(1-X2)*X1*X2)
+                ENDIF
+              ENDIF
+            ENDIF
+            IF (NREJ*REJFAC*HWR().GT.ONE) THEN
+              QMAX=QNOW
+              QLST=QNOW
+              QNOW=-1.
+              GOTO 5
+            ENDIF
+            IF (QLAM.GT.HARDST) HARDST=QLAM
+          ENDIF
+          MPAR=NPAR+1
+          IDPAR(MPAR)=ID1
+          TMPAR(MPAR)=.TRUE.
+          PPAR(1,MPAR)=QNOW*Z1
+          PPAR(2,MPAR)=XI
+          PPAR(4,MPAR)=ENOW*Z1
+          NPAR=NPAR+2
+          IDPAR(NPAR)=ID2
+          TMPAR(NPAR)=.TRUE.
+          PPAR(1,NPAR)=QNOW*Z2
+          PPAR(2,NPAR)=XI
+          PPAR(4,NPAR)=ENOW*Z2
+C---NEW MOTHER-DAUGHTER RELATIONS
+          JDAPAR(1,KPAR)=MPAR
+          JDAPAR(2,KPAR)=NPAR
+          JMOPAR(1,MPAR)=KPAR
+          JMOPAR(1,NPAR)=KPAR
+C---NEW COLOUR CONNECTIONS
+          JCOPAR(3,KPAR)=NPAR
+          JCOPAR(4,KPAR)=MPAR
+          JCOPAR(1,MPAR)=NPAR
+          JCOPAR(2,MPAR)=KPAR
+          JCOPAR(1,NPAR)=KPAR
+          JCOPAR(2,NPAR)=MPAR
+C
+        ENDIF
+      ENDIF
+      IF (QNOW.LT.ZERO) THEN
+C--BRANCHING STOPS
+        IF (ID.EQ.IDPAR(2).AND.PPAR(5,2).GT.1D-6) THEN
+          PPAR(5,KPAR)=PPAR(5,2)**2
+        ELSE
+          PPAR(5,KPAR)=RMASS(ID)**2
+        ENDIF
+        PMOM=PPAR(4,KPAR)**2-PPAR(5,KPAR)
+        IF (PMOM.LT.-1E-6) CALL HWWARN('HWBRAN',104,*999)
+        IF (PMOM.LT.ZERO) PMOM=ZERO
+        PPAR(3,KPAR)=SQRT(PMOM)
+        JDAPAR(1,KPAR)=0
+        JDAPAR(2,KPAR)=0
+        JCOPAR(3,KPAR)=0
+        JCOPAR(4,KPAR)=0
+      ENDIF
+  999 END
+CDECK  ID>, HWBRCN.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBRCN
+C-----------------------------------------------------------------------
+C     SUBROUTINE TO REPLACE HWBCON IN RPARITY VIOLATING SUSY
+C     BASED ON HWBCON BY BRW
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,IST,ID,JC,JD,JHEP,IDP,IDM,IDP2,IDM2,
+     &        RHEP,IST2,ORG,ANTC,XHEP,IP,COLP
+      LOGICAL BVVUSE,BVVHRD,BVDEC1,BVDEC2,COLRD,ACOLRD,BVHRD,BVHRD2,
+     &        BVDEC3
+C--logical functions to decide if baryon number violating
+C--BVDEC1 DELTAB=+1
+      BVDEC1(IP) = ((IDHW(IP).GE.419.AND.IDHW(IP).LE.424).OR.
+     &              IDHW(IP).EQ.411.OR.IDHW(IP).EQ.412.OR.
+     &              IDHW(IP).EQ.449).AND.IDHW(JDAHEP(1,IP)).LE.6.
+     &              AND.IDHW(JDAHEP(1,IP)+1).LE.6.AND.
+     &              IDHW(JDAHEP(2,IP)).LE.6
+C--BVDEC2 DELTAB=-1
+      BVDEC2(IP) = ((IDHW(IP).GE.413.AND.IDHW(IP).LE.418).OR.
+     &              IDHW(IP).EQ.405.OR.IDHW(IP).EQ.406.OR.
+     &              IDHW(IP).EQ.449).AND.
+     &    IDHW(JDAHEP(1,IP)).GE.7.AND.IDHW(JDAHEP(1,IP)).LE.12.AND.
+     &    IDHW(JDAHEP(1,IP)+1).GE.7.AND.IDHW(JDAHEP(1,IP)+1).LE.12.AND.
+     &    IDHW(JDAHEP(2,IP)).GE.7.AND.IDHW(JDAHEP(2,IP)).LE.12
+C--Neutralino and Chargino Decays
+      BVDEC3(IP) = ((IDHW(IP).GE.450.AND.IDHW(IP).LE.457).AND.
+     &   (IDHW(JDAHEP(1,IP)).LE.12.AND.IDHW(JDAHEP(1,IP)+1).LE.12.
+     &    .AND.IDHW(JDAHEP(2,IP)).LE.12))
+C--Now the hard vertices
+      BVHRD(IP) = IDHW(IP).EQ.15.AND.IDHW(JMOHEP(1,IP)).LE.12.
+     &    AND.IDHW(JMOHEP(2,IP)).LE.12.AND.IDHW(JDAHEP(1,IP)).LE.12.
+     &    AND.IDHW(JDAHEP(2,IP)).GE.449.AND.IDHW(JDAHEP(2,IP)).LE.457
+      BVHRD2(IP) = IDHW(IP).EQ.15.AND.IDHW(JMOHEP(1,IP)).LE.12.
+     &    AND.IDHW(JMOHEP(2,IP)).LE.12.AND.IDHW(JDAHEP(1,IP)).GE.198.
+     &    AND.IDHW(JDAHEP(1,IP)).LE.207.
+     &    AND.ABS(IDHEP(JDAHEP(2,IP))).GT.1000000
+C--Those particles which are coloured
+      COLRD(IP) = IP.LE.6.OR.IP.EQ.13.OR.IP.EQ.449.OR.
+     &   (IP.GE.401.AND.IP.LE.406).OR.(IP.GE.413.AND.IP.LE.418).OR.
+     &   (IP.GE.115.AND.IP.LE.120).OR.IP.EQ.59
+C--Those particles which are anticoloured
+      ACOLRD(IP) = (IP.GE.7.AND.IP.LE.12).OR.IP.EQ.13.OR.IP.EQ.449.OR.
+     & (IP.GE.407.AND.IP.LE.412).OR.(IP.GE.419.AND.IP.LE.424).OR.
+     & (IP.GE.109.AND.IP.LE.114).OR.IP.EQ.59
+      IF (IERROR.NE.0) RETURN
+      COLP = 0
+      IF(COLUPD.AND.HRDCOL(1,3).NE.0) THEN
+        JD = 0
+        DO IHEP = HRDCOL(1,3),HRDCOL(1,3)+4
+          JD = JD+1
+          IF(JD.NE.3) THEN
+            JMOHEP(2,IHEP) = HRDCOL(1,JD)
+            JDAHEP(2,IHEP) = HRDCOL(2,JD)
+          ENDIF
+        ENDDO
+        COLUPD=.FALSE.
+        DO IHEP=1,5
+          DO JHEP=1,2
+            HRDCOL(JHEP,IHEP)=0
+          ENDDO
+        ENDDO
+      ELSEIF(COLUPD) THEN
+        RETURN
+      ENDIF
+      DO 110 IHEP=1,NHEP
+      IST=ISTHEP(IHEP)
+      JD =0
+      BVVUSE = .FALSE.
+      BVVHRD = .FALSE.
+C---LOOK FOR PARTONS WITHOUT COLOUR MOTHERS
+      IF ((IST.LT.145.OR.IST.GT.152).AND.IST.NE.155) GOTO 110
+      IF (JMOHEP(2,IHEP).EQ.0) THEN
+C---FIND COLOUR-CONNECTED PARTON
+        IF(IST.EQ.155.AND.ABS(IDHEP(IHEP)).EQ.6) THEN
+          JC = JMOHEP(1,IHEP)
+        ELSEIF(IST.EQ.155) THEN
+          GOTO 110
+        ELSE
+          JC=JMOHEP(1,IHEP)
+        ENDIF
+        IF (IST.NE.152) JC=JMOHEP(1,JC)
+C--Correction for BV
+        IF(HRDCOL(1,1).NE.0) THEN
+          IDP = IDHW(HRDCOL(1,1))
+          IDP2 = 0
+        ELSE
+          IDP  = 0
+          IDP2 = 0
+        ENDIF
+        IDM = JMOHEP(1,JC)
+        IF(BVDEC1(IDM).OR.BVDEC2(IDM)) THEN
+          IF(IDHW(IDM).EQ.449.AND.JDAHEP(1,IDM).EQ.JC) THEN
+            JC=JMOHEP(2,JC)
+          ELSE
+            JD = JMOHEP(2,JC)
+            JC = IDM
+            IF(JC.EQ.JD) JD= JDAHEP(2,JC-1)
+            BVVUSE = .TRUE.
+          ENDIF
+C--NEW FOR BV HARD PROCESS
+        ELSEIF(BVHRD(IDM)) THEN
+          IF(IDHW(JDAHEP(2,JMOHEP(1,JC))).EQ.449) THEN
+            JD   = JMOHEP(2,JC)
+            IDM2 = JDAHEP(2,HRDCOL(1,2))
+            IF(JD.EQ.IDM2) JD = HRDCOL(1,1)
+            IF(JC.EQ.JDAHEP(2,IDM2).AND.COLRD(IDHW(IHEP))) THEN
+              JC = JMOHEP(2,JC)
+            ELSEIF(JC.EQ.IDM2) THEN
+              IF(JDAHEP(2,JMOHEP(2,JC)).EQ.JC) THEN
+                JC = JMOHEP(2,JC)
+              ELSE
+              JMOHEP(2,IHEP)=JMOHEP(2,JC)
+              GOTO 110
+              ENDIF
+            ELSE
+              JC = HRDCOL(1,1)
+              BVVUSE = .TRUE.
+              BVVHRD = .TRUE.
+              IF(ACOLRD(IDHW(IHEP))) JC = JD
+              IF(JC.EQ.IDM2) GOTO 110
+            ENDIF
+          ELSE
+            JC =JMOHEP(2,JC)
+            BVVUSE = .TRUE.
+            BVVHRD = .TRUE.
+          ENDIF
+        ELSEIF(BVHRD2(IDM)) THEN
+          JD = JMOHEP(2,JC)
+            IF(JC.EQ.JDAHEP(2,HRDCOL(1,2))) THEN
+              JMOHEP(2,IHEP)=JMOHEP(2,JC)
+              GOTO 110
+            ENDIF
+          IF(JD.EQ.JDAHEP(2,HRDCOL(1,2))) JD = HRDCOL(1,1)
+          BVVUSE=.TRUE.
+          BVVHRD = .TRUE.
+          IF(JC.EQ.JDAHEP(2,HRDCOL(1,2))) THEN
+            JC = JMOHEP(2,JC)
+          ELSE
+            JC = HRDCOL(1,1)
+          ENDIF
+        ELSE
+          JC =JMOHEP(2,JC)
+        ENDIF
+        IF (JC.EQ.0) CALL HWWARN('HWBCON',51,*110)
+C---FIND SPECTATOR WHEN JC IS DECAYED HEAVY QUARK OR SUSY PARTICLE
+        IF (ISTHEP(JC).EQ.155) THEN
+          IF (IDHEP(JMOHEP(1,JC)).EQ.94) THEN
+C---DECAYED BEFORE HADRONIZING
+            IF(BVVHRD) THEN
+              JHEP = JC
+            ELSEIF(BVVUSE) THEN
+              JHEP=JDAHEP(2,JC-1)
+            ELSE
+              JHEP=JMOHEP(2,JC)
+            ENDIF
+            IF(JHEP.EQ.0.AND.ABS(IDHEP(JC)).EQ.6) THEN
+              JHEP = JMOHEP(1,JMOHEP(1,JC))
+              IF(BVDEC1(JMOHEP(1,JHEP)).OR.BVDEC2(JMOHEP(1,JHEP))) THEN
+                JC = JHEP
+                JHEP = JDAHEP(2,JC-1)
+              ELSE
+                JHEP = 0
+              ENDIF
+            ENDIF
+            IF(BVVUSE.AND.ABS(IDHEP(JHEP)).GT.1000000.AND.
+     &           ISTHEP(JHEP).NE.155.OR.JHEP.EQ.0) GOTO 110
+            ID=IDHW(JHEP)
+            IF (ISTHEP(JHEP).EQ.155) THEN
+C---SPECIAL FOR GLUINO DECAYS
+              IF (ID.EQ.449) THEN
+                ID=IDHW(JC)
+                IF(BVVUSE) THEN
+                  ID=IDHW(IHEP)
+                  IF(ID.LE.6.OR.ID.EQ.13.OR.
+     &               (ID.GE.115.AND.ID.LE.120)) THEN
+                    ID = 7
+                  ELSE
+                    ID = 1
+                  ENDIF
+                ENDIF
+                CALL HWBRC1(JC,ID,JHEP,.TRUE.,*999)
+                IF(BVVUSE.AND.JMOHEP(1,JC).EQ.JMOHEP(1,JD)) JC =JD
+              ELSE
+                JC=JDAHEP(2,JHEP)
+                IF(COLRD(IDHW(IHEP)).AND.IDHW(JDAHEP(1,JHEP)).EQ.449)
+     &             JC=JDAHEP(1,JHEP)
+                IF(BVVUSE.AND.JMOHEP(1,JC).EQ.JMOHEP(1,JD)) JC =JD
+              ENDIF
+            ELSE
+              IF(BVVUSE) THEN
+                IF(BVDEC2(JMOHEP(1,JHEP)).OR.JD.NE.JHEP.OR.
+     &            BVHRD(JMOHEP(1,JHEP)).OR.BVHRD2(JMOHEP(1,JHEP))) THEN
+                  JC = JD
+                  GOTO 100
+                ELSE
+                  JMOHEP(2,IHEP)=JHEP
+                  ID = IDHW(JHEP)
+                  IF((ID.GE.7.AND.ID.LE.12).OR.
+     &               (ID.GE.109.AND.ID.LE.114)) JMOHEP(2,JHEP)=IHEP
+                ENDIF
+              ELSE
+C--new for particles connected to BV
+                IDM = JMOHEP(1,JHEP)
+                IF(BVDEC1(IDM).OR.BVHRD(IDM).OR.BVHRD2(IDM)) THEN
+                  JC = JHEP
+                  IF(ABS(IDHEP(IHEP)).LT.1000000) GOTO 100
+                  JMOHEP(2,IHEP)=JHEP
+                  GOTO 110
+                ENDIF
+C--new for top's from BV
+                ID = IDHW(JC)
+                IDP  = JMOHEP(1,JMOHEP(1,JMOHEP(1,JC)))
+                IF((ID.EQ.6.AND.(BVDEC1(IDP))).
+     &              OR.(ID.EQ.12.AND.BVDEC2(IDP)).
+     &              OR.((ID.EQ.12.OR.ID.EQ.449).AND.BVHRD(IDP))) THEN
+                   JMOHEP(2,IHEP)=JHEP
+                   IF(JDAHEP(2,JHEP).EQ.JC) JDAHEP(2,JHEP)=IHEP
+                ELSE
+                  IF((IDHW(IHEP).GE.7.AND.IDHW(IHEP).LE.12.
+     &               AND.IDHW(JHEP).GE.7.AND.IDHW(JHEP).LE.12).OR.
+     &               (IDHW(IHEP).LE.6.AND.IDHW(JHEP).LE.6)) THEN
+                    JMOHEP(2,IHEP)=JHEP
+                  ELSE
+                    JMOHEP(2,IHEP)=JHEP
+                    IF((COLRD(IDHW(IHEP)).AND.ACOLRD(IDHW(JHEP))).OR.
+     &                (.NOT.COLRD(IDHW(IHEP)).AND.
+     &                .NOT.ACOLRD(IDHW(JHEP)))) THEN
+                      IF(JDAHEP(2,JHEP).EQ.0) THEN
+                        JDAHEP(2,JHEP)=IHEP
+                      ELSEIF(JMOHEP(2,JDAHEP(2,JHEP)).NE.JHEP) THEN
+                        JDAHEP(2,JHEP)=IHEP
+                      ENDIF
+                    ELSE
+                      IF(JMOHEP(2,JHEP).EQ.JC) JMOHEP(2,JHEP)=IHEP
+                    ENDIF
+                  ENDIF
+                ENDIF
+              ENDIF
+              GOTO 110
+            ENDIF
+          ELSE
+            JC=JMOHEP(2,JC)
+          ENDIF
+        ENDIF
+ 100    CONTINUE
+        IF(BVVUSE.AND.ABS(IDHEP(JC)).LT.1000000.AND.JC.NE.JD
+     &     .AND.JD.NE.0.AND.JD.NE.JMOHEP(1,JC)) JC = JD
+        IF(BVVUSE.AND.ABS(IDHEP(JC)).GT.1000000) THEN
+          IF(COLRD(IDHW(IHEP)).AND..NOT.BVVHRD) GOTO 110
+        ENDIF
+        IF(BVVUSE.AND.ISTHEP(JC).EQ.149) JC=JMOHEP(1,JMOHEP(1,JC))
+C--SEARCH IN THE JET
+        IF((ISTHEP(JC).GT.145.AND.ISTHEP(JC).LT.152).AND.
+     &     ISTHEP(IHEP).EQ.155) THEN
+          JMOHEP(2,IHEP) = JC
+          GOTO 110
+        ENDIF
+        CALL HWBRC2(COLP,IHEP,JC,.TRUE.,BVVUSE,BVVHRD)
+        IF(COLP.NE.0) THEN
+          JMOHEP(2,IHEP) = COLP
+          IF(COLRD(IDHW(IHEP)).AND.ACOLRD(IDHW(COLP)).
+     &       AND.JDAHEP(2,COLP).EQ.0)
+     &      JDAHEP(2,COLP) = IHEP
+          IF((IDHW(IHEP).GE.7.AND.IDHW(IHEP).LE.12).AND.
+     &       (IDHW(COLP).GE.7.AND.IDHW(COLP).LE.12)) THEN
+             IF(JMOHEP(2,COLP).EQ.0) JMOHEP(2,COLP) = IHEP
+          ENDIF
+        ENDIF
+      ENDIF
+  110 CONTINUE
+C---BREAK COLOUR CONNECTIONS WITH PHOTONS modified for Rslash
+      IHEP=1
+  130 IF (IHEP.LE.NHEP) THEN
+        IF (IDHW(IHEP).EQ.59 .AND. ISTHEP(IHEP).EQ.149.AND.
+     &      (JMOHEP(2,IHEP).NE.IHEP.OR.JDAHEP(2,IHEP).NE.IHEP)) THEN
+          IF(JMOHEP(2,IHEP).NE.0) THEN
+          IF (JDAHEP(2,JMOHEP(2,IHEP)).EQ.IHEP)
+     &      JDAHEP(2,JMOHEP(2,IHEP))=JDAHEP(2,IHEP)
+          ENDIF
+          IF (JDAHEP(2,IHEP).NE.0) THEN
+            IF (JMOHEP(2,JDAHEP(2,IHEP)).EQ.IHEP)
+     &        JMOHEP(2,JDAHEP(2,IHEP))=JMOHEP(2,IHEP)
+          ENDIF
+          DO RHEP=1,NHEP
+            IST=ISTHEP(RHEP)
+            IF((IST.GE.147.AND.IST.LE.149).AND.JDAHEP(2,RHEP).EQ.IHEP)
+     &        JDAHEP(2,RHEP)=JMOHEP(2,IHEP)
+          ENDDO
+          DO RHEP=1,NHEP
+            IST=ISTHEP(RHEP)
+            IF((IST.GE.147.AND.IST.LE.149).AND.JMOHEP(2,RHEP).EQ.IHEP)
+     &        JMOHEP(2,RHEP) = JDAHEP(2,IHEP)
+          ENDDO
+          JMOHEP(2,IHEP)=IHEP
+          JDAHEP(2,IHEP)=IHEP
+        ENDIF
+        IHEP=IHEP+1
+        GOTO 130
+      ENDIF
+C--Update the BV anticolour corrections
+      DO 210 IHEP=1,NHEP+1
+      IF(IHEP.EQ.1) GOTO 210
+      IST2 = 0
+      IF(IHEP.EQ.NHEP+1) THEN
+        ANTC = HRDCOL(1,1)
+        IF(ANTC.EQ.0.OR.(IDHW(JMOHEP(1,HRDCOL(1,2))).LE.6)) GOTO 210
+        IST=155
+        XHEP=HRDCOL(1,2)
+        IF(ANTC.EQ.JDAHEP(2,XHEP)) ANTC=JDAHEP(1,JDAHEP(1,ANTC))
+        IF(ANTC.NE.0.AND.JDAHEP(1,ANTC).NE.0) IST2=ISTHEP(ANTC)
+      ELSE
+        ANTC = JDAHEP(2,IHEP-1)
+        IF(ANTC.NE.0) IST2=ISTHEP(ANTC)
+        IST=ISTHEP(IHEP)
+        IDM = IDHW(IHEP)
+        XHEP=IHEP
+      ENDIF
+      JC = 0
+      JHEP = 0
+      JD = 0
+      ORG = 0
+      IF(IST.EQ.155.AND.IST2.EQ.155) THEN
+        IDM = IDHW(XHEP)
+        ORG = ANTC
+        IF(BVDEC1(XHEP).OR.BVDEC2(XHEP).OR.BVHRD(XHEP).OR.
+     &     BVHRD2(XHEP)) THEN
+          JC=ANTC
+          ID = IDHW(JC)
+          JHEP = JC
+          IF(BVDEC1(JC).OR.BVDEC2(JC)) THEN
+            IF(IHEP.EQ.(NHEP+1)) ANTC=JDAHEP(1,JC)
+            GOTO 200
+          ENDIF
+          IF (ID.EQ.449) THEN
+C--SPECIAL FOR GLUINO DECAYS
+            ID=IDHW(XHEP)
+            IF(IHEP.EQ.NHEP+1) ID = 407
+            CALL HWBRC1(JC,ID,JHEP,.FALSE.,*999)
+          ELSE
+            IF(IDHW(JDAHEP(1,JHEP)).EQ.449) THEN
+              JC=JDAHEP(1,JHEP)
+            ELSE
+              JC=JDAHEP(2,JHEP)
+            ENDIF
+          ENDIF
+C--SEARCH IN JET
+          CALL HWBRC2(COLP,XHEP,JC,.FALSE.,BVVUSE,.FALSE.)
+          ANTC = COLP
+          IF(IHEP.LE.NHEP.AND.ACOLRD(IDHW(IHEP)).AND.
+     &       COLRD(IDHW(COLP)).AND.JMOHEP(2,COLP).EQ.0) THEN
+             JMOHEP(2,COLP) = IHEP
+          ELSEIF(IHEP.LE.NHEP.AND.IDHW(IHEP).LE.6.AND.
+     &       IDHW(COLP).LE.6.AND.JDAHEP(2,COLP).EQ.0) THEN
+             JDAHEP(2,COLP) = IHEP
+          ELSEIF(IHEP.GT.NHEP.AND.
+     &       ((BVHRD(XHEP).AND.COLRD(JDAHEP(1,XHEP))).
+     &       OR.(BVHRD2(XHEP).AND.ACOLRD(JDAHEP(2,XHEP)))).AND.
+     &       ACOLRD(IDHW(COLP)).AND.JDAHEP(2,COLP).EQ.0) THEN
+            JDAHEP(2,COLP) = IHEP
+          ENDIF
+        ENDIF
+      ENDIF
+  200 CONTINUE
+      IF(IHEP.EQ.NHEP+1) THEN
+        IF(HRDCOL(1,1).NE.ANTC.AND.ANTC.NE.0) THEN
+          HRDCOL(1,1)=ANTC
+        IF(JDAHEP(2,ANTC).EQ.IHEP) THEN
+          IF(JDAHEP(2,JMOHEP(1,HRDCOL(1,2))).EQ.JDAHEP(2,HRDCOL(1,2)).
+     &    AND.JMOHEP(2,JDAHEP(2,HRDCOL(1,2))).EQ.JMOHEP(1,HRDCOL(1,2)))
+     &      THEN
+            JDAHEP(2,ANTC) = JMOHEP(2,HRDCOL(1,2))
+          ELSE
+            JDAHEP(2,ANTC) = JMOHEP(1,HRDCOL(1,2))
+          ENDIF
+        ELSEIF(JMOHEP(2,ANTC).EQ.IHEP) THEN
+          JMOHEP(2,ANTC) = JMOHEP(1,HRDCOL(1,2))
+        ENDIF
+        ENDIF
+      ELSEIF(IHEP.NE.1) THEN
+        IF(JDAHEP(2,IHEP-1).NE.ANTC.AND.ANTC.NE.0) JDAHEP(2,IHEP-1)=ANTC
+      ENDIF
+ 210  CONTINUE
+C--Update BV decaying particles connections
+      DO 310 IHEP=1,NHEP+1
+      IF(IHEP.EQ.1) GOTO 310
+      IF(IHEP.EQ.NHEP+1) THEN
+        ANTC=HRDCOL(1,1)
+        IF(ANTC.EQ.0.OR.IDHW(JDAHEP(1,HRDCOL(1,2))).LE.6) GOTO 310
+        IST=155
+        XHEP=HRDCOL(1,2)
+        IF(ANTC.EQ.JDAHEP(2,XHEP)) ANTC=JDAHEP(1,JDAHEP(1,ANTC))
+      ELSE
+        ANTC=JMOHEP(2,IHEP)
+        IST=ISTHEP(IHEP)
+        IDM = IDHW(IHEP)
+        XHEP=IHEP
+      ENDIF
+      IST2 = 0
+      JC = 0
+      JD = 0
+      IF(ANTC.NE.0.AND.IHEP.NE.NHEP+1) THEN
+        IF(JDAHEP(1,ANTC).NE.0) IST2 = ISTHEP(ANTC)
+      ELSEIF(ANTC.NE.0.AND.IHEP.EQ.NHEP+1) THEN
+        IST2=ISTHEP(ANTC)
+      ENDIF
+      IF(IST.EQ.155.AND.IST2.EQ.155) THEN
+        IF(BVDEC2(XHEP).OR.BVHRD(XHEP).OR.BVHRD2(XHEP)) THEN
+C--FIND COLOUR CONNECTED PARTON
+          JC = ANTC
+          ID=IDHW(JC)
+          JHEP = JC
+          IF(BVDEC2(JHEP)) THEN
+             ANTC=JC
+             GOTO 300
+          ENDIF
+          IF (ID.EQ.449) THEN
+            ID=IDHW(XHEP)
+            IF(IHEP.EQ.NHEP+1) ID = 401
+C--SPECIAL FOR GLUINO DECAYS
+            CALL HWBRC1(JC,ID,JHEP,.TRUE.,*999)
+          ELSE
+            IF(IDHW(JDAHEP(1,JHEP)).EQ.449) THEN
+              JC=JDAHEP(1,JHEP)
+            ELSE
+              JC=JDAHEP(2,JHEP)
+            ENDIF
+          ENDIF
+C--SEARCH IN JET
+          CALL HWBRC2(COLP,XHEP,JC,.TRUE.,BVVUSE,.FALSE.)
+          ANTC = COLP
+          IF(COLP.EQ.0) GOTO 300
+          IF(IHEP.LE.NHEP) THEN
+            IF(JDAHEP(2,COLP).EQ.0) THEN
+              JDAHEP(2,COLP) = JDAHEP(2,IHEP)
+            ELSEIF(JMOHEP(2,JDAHEP(2,COLP)).NE.COLP) THEN
+              JDAHEP(2,COLP) = JDAHEP(2,IHEP)
+            ENDIF
+          ELSEIF(IHEP.GT.NHEP.AND.
+     &       ((BVHRD(XHEP).AND.ACOLRD(JDAHEP(1,XHEP)).AND.
+     &       IDHW(JDAHEP(2,XHEP)).EQ.449).
+     &       OR.(BVHRD2(XHEP).AND.ACOLRD(JDAHEP(2,XHEP)))).AND.
+     &       ACOLRD(IDHW(COLP)).AND.JDAHEP(2,COLP).EQ.0) THEN
+            JDAHEP(2,COLP) = IHEP
+          ENDIF
+        ENDIF
+      ENDIF
+  300 CONTINUE
+      IF(IHEP.NE.NHEP+1.AND.IHEP.NE.1) THEN
+        IF(JMOHEP(2,IHEP).NE.ANTC.AND.ANTC.NE.0) JMOHEP(2,IHEP)=ANTC
+      ELSEIF(IHEP.GT.NHEP) THEN
+        IF(HRDCOL(1,1).NE.ANTC.AND.ANTC.NE.0) HRDCOL(1,1)=ANTC
+        IF(ANTC.EQ.0) GOTO 310
+        IF(JDAHEP(2,ANTC).EQ.IHEP) THEN
+          IF(JDAHEP(2,JMOHEP(1,HRDCOL(1,2))).EQ.JDAHEP(2,HRDCOL(1,2)).
+     &    AND.JMOHEP(2,JDAHEP(2,HRDCOL(1,2))).EQ.JMOHEP(1,HRDCOL(1,2)))
+     &      THEN
+            JDAHEP(2,ANTC) = JMOHEP(2,HRDCOL(1,2))
+          ELSE
+            JDAHEP(2,ANTC) = JMOHEP(1,HRDCOL(1,2))
+          ENDIF
+        ELSEIF(JMOHEP(2,ANTC).EQ.IHEP) THEN
+          JMOHEP(2,ANTC) = JMOHEP(1,HRDCOL(1,2))
+        ENDIF
+      ENDIF
+ 310  CONTINUE
+C--Update partons connected to decaying SUSY particle
+      DO 400 IHEP=1,NHEP
+      IST=ISTHEP(IHEP)
+C--LOOK FOR PARTONS CONNECTED TO A DECAYING SUSY PARTICLE
+      IF (IST.LT.145.OR.IST.GT.152) GOTO 400
+      IF(JMOHEP(2,IHEP).EQ.0) GOTO 400
+      IF(ISTHEP(JMOHEP(2,IHEP)).EQ.155) THEN
+C--FIND THE COLOUR CONNECTED PARTON
+        JC=JMOHEP(2,IHEP)
+        ID=IDHW(JC)
+        JHEP = JC
+        IF(BVDEC2(JC).AND.IDHW(JC).NE.449) GOTO 400
+        IF (ID.EQ.449) THEN
+C--SPECIAL FOR GLUINO DECAYS
+          ID=IDHW(IHEP)
+          CALL HWBRC1(JC,ID,JHEP,.TRUE.,*999)
+        ELSE
+          ID=IDHW(IHEP)
+          IF(COLRD(ID).AND.IDHW(JDAHEP(1,JC)).EQ.449) THEN
+            JC=JDAHEP(1,JHEP)
+          ELSE
+            JC=JDAHEP(2,JHEP)
+          ENDIF
+        ENDIF
+C--SEARCH IN JET
+        CALL HWBRC2(COLP,IHEP,JC,.TRUE.,BVVUSE,.FALSE.)
+        JMOHEP(2,IHEP) = COLP
+      ENDIF
+ 400  CONTINUE
+C--Update partons connected to decaying SUSY particle
+      DO 500 IHEP=1,NHEP
+      IST=ISTHEP(IHEP)
+C--LOOK FOR PARTONS CONNECTED TO A DECAYING SUSY PARTICLE
+      IF (IST.LT.145.OR.IST.GT.152) GOTO 500
+      IF(JDAHEP(2,IHEP).EQ.0) GOTO 500
+      IF(ISTHEP(JDAHEP(2,IHEP)).EQ.155) THEN
+C--FIND THE COLOUR CONNECTED PARTON
+        JC=JDAHEP(2,IHEP)
+        ID=IDHW(JC)
+        ID=IDHW(JC)
+        IF (ID.EQ.449) THEN
+          ID=IDHW(IHEP)
+C--SPECIAL FOR GLUINO DECAYS
+          JHEP = JC
+          CALL  HWBRC1(JC,ID,JHEP,.FALSE.,*999)
+        ELSE
+          IF(ACOLRD(IDHW(IHEP)).AND.IDHW(JDAHEP(1,JC)).EQ.449) THEN
+            JC = JDAHEP(1,JC)
+          ELSE
+            JC=JDAHEP(2,JC)
+          ENDIF
+        ENDIF
+C--SEARCH IN THE JET
+        CALL HWBRC2(COLP,IHEP,JC,.FALSE.,BVVUSE,.FALSE.)
+        IF(COLP.NE.0) JDAHEP(2,IHEP) = COLP
+      ENDIF
+ 500  CONTINUE
+C--Flavour and anticolour connections in Rslash
+      DO 610 IHEP=1,NHEP
+        IST=ISTHEP(IHEP)
+        IF(IST.LT.145.OR.IST.GT.152.OR.JDAHEP(2,IHEP).NE.0) GOTO 610
+        JD = 0
+        BVVUSE = .FALSE.
+        JC = JMOHEP(1,IHEP)
+        IF(IST.NE.152) JC = JMOHEP(1,JC)
+        IF(JC.EQ.0) CALL HWWARN('HWBRCN',51,*610)
+C--For particles which came from a top decay
+        IF(ABS(IDHEP(JMOHEP(1,JC))).EQ.6) THEN
+          JD = JMOHEP(1,JMOHEP(1,JMOHEP(1,JC)))
+C--flavour connect to self if needed
+          IF(JDAHEP(2,JMOHEP(1,JC)-1).EQ.JMOHEP(1,JC)) THEN
+            JDAHEP(2,IHEP) = IHEP
+            GOTO 610
+          ELSEIF(JDAHEP(2,JMOHEP(1,JC)-1).NE.0) THEN
+            JDAHEP(2,IHEP) = JDAHEP(2,JMOHEP(1,JC)-1)
+            GOTO 610
+          ELSE
+            JC = JD
+          ENDIF
+        ENDIF
+C--Decide if this came from a BV decay
+        IDM = JMOHEP(1,JC)
+        IF(BVDEC1(IDM).OR.BVDEC2(IDM).OR.BVDEC3(IDM).
+     &     OR.BVHRD(IDM).OR.BVHRD2(IDM)) THEN
+C--Do BV piece
+          IF(JDAHEP(2,JC).EQ.JMOHEP(1,JC)) THEN
+           IF(IDHW(JMOHEP(1,JC)).EQ.449.AND.
+     &        JDAHEP(1,JMOHEP(1,JC)).EQ.JC) THEN
+              JC = JDAHEP(2,JMOHEP(1,JC)-1)
+            ELSE
+              JC = JMOHEP(2,JMOHEP(1,JC))
+            ENDIF
+            IF(ABS(IDHEP(JC)).LT.1000000) THEN
+              IF(JDAHEP(1,JC).EQ.0) THEN
+                JDAHEP(2,IHEP) = JC
+                GOTO 610
+              ELSE
+                GOTO 600
+              ENDIF
+            ELSEIF(ABS(IDHEP(JC)).GT.1000000
+     &        .AND.ISTHEP(JC).NE.155) THEN
+              GOTO 610
+            ENDIF
+            IF(ISTHEP(JC).EQ.155.AND.ACOLRD(IDHW(IHEP))) THEN
+              JC = JDAHEP(1,JC)
+            ELSE
+              IF(ISTHEP(JC).EQ.155.AND.IDHW(JDAHEP(1,JC)).NE.449) THEN
+                JC = JDAHEP(1,JC)
+              ELSE
+                JC = JDAHEP(2,JC)
+              ENDIF
+            ENDIF
+          ELSE
+C--For the hard process
+            IF(IDHW(IDM).EQ.15.AND.JC.EQ.JDAHEP(2,JMOHEP(1,JC))) THEN
+              JDAHEP(2,IHEP) = JDAHEP(2,JC)
+              GOTO 610
+            ELSEIF(IDHW(IDM).EQ.15.AND.IDHW(IHEP).NE.449) THEN
+              JD=HRDCOL(1,1)
+              IF(BVHRD(IDM).AND.IDHW(JDAHEP(2,IDM)).NE.449) THEN
+                JC = JDAHEP(2,JC)
+                GOTO 600
+              ELSEIF(JMOHEP(1,JDAHEP(2,JC)).EQ.JD) THEN
+                JC=JDAHEP(2,JC)
+                GOTO 600
+              ENDIF
+              IF(JDAHEP(2,JC).EQ.8) JC = JD
+            ELSE
+              JD=JMOHEP(2,JMOHEP(1,JC))
+            ENDIF
+            IF(COLRD(IDHW(IHEP)).AND..NOT.ACOLRD(IDHW(IHEP)).AND.
+     &      ABS(IDHEP(JD)).GT.1000000.AND.ISTHEP(JD).NE.155) THEN
+              JDAHEP(2,IHEP) = JD
+              IF(JDAHEP(2,JD).EQ.0) JDAHEP(2,JD) = IHEP
+            ENDIF
+            IF(ABS(IDHEP(JD)).GT.1000000
+     &        .AND.ISTHEP(JD).NE.155) GOTO 610
+            IF(ISTHEP(JC).EQ.149) THEN
+              JDAHEP(2,IHEP)=JC
+              GOTO 610
+            ENDIF
+          IF(ACOLRD(IDHW(IHEP)).AND.IDHW(JC).EQ.449.AND.BVDEC2(JC)) THEN
+              JC = JDAHEP(1,JC)
+            ELSE
+              JC = JDAHEP(2,JC)
+            ENDIF
+          ENDIF
+C--SEARCH IN THE JET
+ 600      CALL HWBRC2(COLP,IHEP,JC,.FALSE.,BVVUSE,.FALSE.)
+          IF(COLP.NE.0) THEN
+            IF(ABS(IDHEP(COLP)).EQ.6.AND.JDAHEP(1,COLP).NE.0) THEN
+              IF(ISTHEP(COLP).EQ.155) THEN
+                JC = JDAHEP(2,COLP)
+              ELSE
+                JC = JDAHEP(2,JDAHEP(2,COLP))
+              ENDIF
+              GOTO 600
+            ENDIF
+            JDAHEP(2,IHEP) = COLP
+          ENDIF
+        ELSE
+C--check if it came from a top
+          IF(ABS(IDHEP(JC)).EQ.6) THEN
+C--start the analysis again
+            JC = JMOHEP(1,IHEP)
+            IF(IST.NE.152) JC = JMOHEP(1,JC)
+            JC = JDAHEP(2,JC)
+            IF(JC.EQ.0) CALL HWWARN('HWBRCN',52,*610)
+              IF(ISTHEP(JC).EQ.155) THEN
+                IF (IDHEP(JMOHEP(1,JC)).EQ.94) THEN
+C---DECAYED BEFORE HADRONIZING
+                  JHEP=JDAHEP(2,JC-1)
+                  IF (JHEP.EQ.0) GO TO 610
+                  ID=IDHW(JHEP)
+                  IF (ISTHEP(JHEP).EQ.155) THEN
+C---SPECIAL FOR GLUINO DECAYS
+                    IF (ID.EQ.449) THEN
+                      CALL HWBRC1(JC,ID,JHEP,.TRUE.,*999)
+                    ELSE
+                      JC=JDAHEP(2,JHEP)
+                    ENDIF
+                  ELSE
+                    IF(JMOHEP(2,JHEP).EQ.JC) JMOHEP(2,JHEP)=IHEP
+                    JDAHEP(2,IHEP) = JHEP
+                    GOTO 610
+                  ENDIF
+                ELSE
+                  JC=JDAHEP(2,JC-1)
+                ENDIF
+              ENDIF
+C--SEARCH IN JET
+              CALL HWBRC2(COLP,IHEP,JC,.FALSE.,BVVUSE,.FALSE.)
+              IF(COLP.NE.0) JDAHEP(2,IHEP) = COLP
+          ELSE
+            CALL HWWARN('HWBRCN',100,*610)
+          ENDIF
+        ENDIF
+ 610  CONTINUE
+ 999  END
+CDECK  ID>, HWBRC1.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    PeterRichardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBRC1(JC,ID,JHEP,COL,*)
+C-----------------------------------------------------------------------
+C--Function to find the right daugther of a decaying gluino
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER ID,JHEP,KC,JC
+      LOGICAL COL
+C---N.B. WILL NEED MODS WHEN SUSY PARTICLES CAN SHOWER
+C--Rparity take the first daughther
+      IF(IDHW(JDAHEP(1,JHEP)).LE.12.AND.IDHW(JDAHEP(1,JHEP)+1).LE.12
+     &   .AND.IDHW(JDAHEP(2,JHEP)).LE.12) THEN
+        KC = JDAHEP(1,JHEP)
+        GOTO 20
+      ELSEIF ((COL.AND.(ID.EQ.449.OR.ID.EQ.13)).OR.
+     &        (ID.GE.401.AND.ID.LE.406).OR.
+     &       (ID.GE.413.AND.ID.LE.418).OR.ID.LE.6.OR.
+     &       (ID.GE.115.AND.ID.LE.120)) THEN
+C---LOOK FOR ANTI(S)QUARK OR GLUON
+        DO KC=JDAHEP(1,JHEP),JDAHEP(2,JHEP)
+          ID=IDHW(KC)
+          IF ((ID.GE.7.AND.ID.LE.13).OR.(ID.GE.407.AND.ID.LE.412).OR.
+     &       (ID.GE.419.AND.ID.LE.424)) GOTO 20
+        ENDDO
+      ELSE
+C---LOOK FOR (S)QUARK OR GLUON
+        DO KC=JDAHEP(1,JHEP),JDAHEP(2,JHEP)
+          ID=IDHW(KC)
+          IF (ID.LE.  6.OR. ID.EQ. 13.OR.(ID.GE.401.AND.ID.LE.406).OR.
+     &       (ID.GE.413.AND.ID.LE.418)) GOTO 20
+        ENDDO
+      ENDIF
+C---COULDNT FIND ONE
+      CALL HWWARN('HWBRC1',100,*10)
+ 10   RETURN 1
+ 20   JC=KC
+      END
+CDECK  ID>, HWBRC2.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBRC2(COLP,IHEP,JC,CON,BVVUSE,BVVHRD)
+C-----------------------------------------------------------------------
+C--Function to search in the jet for the particle
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER JC,JD,QHEP,LHEP,IHEP,JHEP,IDM,NCOUNT,ID,IP,IDM2,COLP
+      LOGICAL CON,BVVUSE,FLA,AFLA,BVVHRD
+      FLA(IP)  = (IP.LE.6.OR.(IP.GE.115.AND.IP.LE.120).
+     &           OR.(IP.GE.401.AND.IP.LE.406).
+     &           OR.(IP.GE.413.AND.IP.LE.418))
+      AFLA(IP) = ((IP.LE.12.AND.IP.GE.7).OR.(IP.GE.109.AND.IP.LE.114).
+     &           OR.(IP.GE.407.AND.IP.LE.412).
+     &           OR.(IP.GE.419.AND.IP.LE.424))
+      ID = IDHW(IHEP)
+      COLP = 0
+C--begining and end of jet
+      IF(JDAHEP(1,JC).NE.0) THEN
+        JC=JDAHEP(1,JC)
+        JD=JDAHEP(2,JC)
+      ELSE
+        COLP = JC
+        RETURN
+      ENDIF
+      IF (JD.LT.JC) JD=JC
+      LHEP=0
+      IF(CON) THEN
+C--SEARCH FOR A COLOUR PARTNER
+        DO 110 JHEP=JC,JD
+          IDM = IDHW(JHEP)
+        IF (ISTHEP(JHEP).LT.145.OR.ISTHEP(JHEP).GT.152) GOTO 110
+        IF(AFLA(ID).AND.IDM.EQ.13) GOTO 110
+        IF (JDAHEP(2,JHEP).EQ.IHEP) LHEP=JHEP
+        IF ((BVVUSE.AND.JMOHEP(2,JHEP).NE.0).OR.
+     &      (.NOT.BVVUSE.AND.JDAHEP(2,JHEP).NE.0)) GOTO 110
+        IF(BVVUSE.AND.ABS(IDHEP(JHEP)).GT.1000000) THEN
+          IF(BVVHRD.AND.AFLA(ID)) THEN
+            CONTINUE
+          ELSE
+            RETURN
+          ENDIF
+        ENDIF
+        IF(BVVUSE.AND.(
+     &      ((FLA(ID).OR.ID.EQ.13.OR.ID.EQ.449).AND.AFLA(IDM)).
+     &  OR.(AFLA(ID).AND.(FLA(IDM).OR.IDM.EQ.13.OR.IDM.EQ.449))))
+     &     GOTO 110
+        IF(AFLA(ID).AND.(IDM.EQ.59.OR.IDM.EQ.449.OR.IDM.EQ.13)) GOTO 110
+C---JOIN IHEP AND JHEP
+        COLP=JHEP
+        IF(BVVUSE.OR.(ID.GE.7.AND.ID.LE.12.
+     &     AND.((IDM.GE.7.AND.IDM.LE.12)))) RETURN
+        IF(IHEP.NE.HRDCOL(1,2).AND.
+     &     (((FLA(ID).OR.ID.EQ.13.OR.ID.EQ.449.OR.ID.EQ.59)
+     &       .AND.(AFLA(IDM).OR.IDM.EQ.13.OR.IDM.EQ.449.OR.IDM.EQ.59))
+     &     .OR.(AFLA(ID).AND.(FLA(IDM).OR.IDM.EQ.59))))
+     &    JDAHEP(2,JHEP)=IHEP
+        RETURN
+ 110    CONTINUE
+        IF (LHEP.NE.0) COLP=LHEP
+C--Additional Baryon number violating piece
+        IF(COLP.EQ.0) THEN
+          IDM2= IDHW(JC)
+         IF(JMOHEP(1,JC).LT.6) THEN
+           IF(IDM2.LE.6) THEN
+             IDM2= IDM2+6
+           ELSEIF(IDM2.GT.6) THEN
+             IDM2=IDM2-6
+           ENDIF
+         ENDIF
+          IF(IHEP.EQ.HRDCOL(1,2).OR.
+     &     ((FLA(ID).OR.ID.EQ.13.OR.ID.EQ.449.OR.ID.EQ.15.OR.ID.EQ.59)
+     &       .AND.(AFLA(IDM2).OR.IDM2.EQ.13.OR.IDM2.EQ.13))) THEN
+              QHEP = JD+1
+ 12           QHEP = QHEP-1
+              IF(IDHEP(QHEP).EQ.0) GOTO 12
+              IF(IDHW(QHEP).EQ.59) THEN
+              IF(JC.EQ.JD.AND.IDHW(JMOHEP(1,QHEP)).EQ.59) THEN
+                COLP = IHEP
+                RETURN
+              ELSE
+                GOTO 12
+              ENDIF
+              ENDIF
+              NCOUNT = 0
+ 11           IF(JDAHEP(2,QHEP).NE.0) THEN
+                IF(JMOHEP(2,JDAHEP(2,QHEP)).EQ.QHEP.AND.
+     &             JDAHEP(2,QHEP).NE.QHEP) THEN
+                 IF(JDAHEP(2,QHEP).GE.JC.AND.JDAHEP(2,QHEP).LE.JD) THEN
+                   QHEP = JDAHEP(2,QHEP)
+                   NCOUNT = NCOUNT+1
+                   IF(NCOUNT.LT.NHEP) GOTO 11
+                 ENDIF
+                ENDIF
+              ENDIF
+            ELSE
+            QHEP = JC
+ 13         QHEP = QHEP+1
+            IF(IDHEP(QHEP).EQ.0) GOTO 13
+            IF(IDHW(QHEP).EQ.59) THEN
+              IF(JC.EQ.JD.AND.IDHW(JMOHEP(1,QHEP)).EQ.59) THEN
+                COLP = IHEP
+                RETURN
+              ELSE
+                GOTO 13
+              ENDIF
+            ENDIF
+            NCOUNT = 0
+ 9          IF(JMOHEP(2,QHEP).NE.0) THEN
+            IF(JDAHEP(2,JMOHEP(2,QHEP)).EQ.QHEP.AND.
+     &         JMOHEP(2,QHEP).NE.QHEP) THEN
+               IF(JMOHEP(2,QHEP).GE.JC.AND.JMOHEP(2,QHEP).LE.JD) THEN
+                 QHEP = JMOHEP(2,QHEP)
+                 NCOUNT = NCOUNT+1
+                 IF(NCOUNT.LT.NHEP) GOTO 9
+               ENDIF
+            ENDIF
+            ENDIF
+          ENDIF
+          IF(ABS(IDHEP(QHEP)).LT.1000000) COLP=QHEP
+        ENDIF
+      ELSE
+C--Search for an anticolour partner
+        DO 210 JHEP=JC,JD
+        IF (ISTHEP(JHEP).LT.145.OR.ISTHEP(JHEP).GT.152) GOTO 210
+        IF (JMOHEP(2,JHEP).EQ.IHEP) LHEP=JHEP
+        IF (JMOHEP(2,JHEP).NE.0) GOTO 210
+C---JOIN IHEP AND JHEP
+        COLP=JHEP
+        RETURN
+ 210   CONTINUE
+       IF (LHEP.NE.0) COLP=LHEP
+C--New piece
+       IF(COLP.EQ.0) THEN
+         IDM2=IDHW(JC)
+         IF(JMOHEP(1,JC).LT.6) THEN
+           IF(IDM2.LE.6) THEN
+             IDM2= IDM2+6
+           ELSEIF(IDM2.GT.6) THEN
+             IDM2=IDM2-6
+           ENDIF
+         ENDIF
+C--Additional Baryon number violating piece
+        IF((FLA(ID).AND.AFLA(IDM2)).OR.
+     & ((AFLA(ID).OR.ID.EQ.13.OR.ID.EQ.449.OR.ID.EQ.15.OR.ID.EQ.59)
+     &    .AND.(FLA(IDM2).OR.IDM2.EQ.13.OR.IDM2.EQ.449))) THEN
+         QHEP = JC
+ 211     QHEP = QHEP+1
+         IF(IDHEP(QHEP).EQ.0) GOTO 211
+         IF(IDHW(QHEP).EQ.59) THEN
+           IF(JC.EQ.JD.AND.IDHW(JMOHEP(1,QHEP)).EQ.59) THEN
+             COLP = IHEP
+             RETURN
+           ELSE
+             GOTO 211
+           ENDIF
+         ENDIF
+         NCOUNT = 0
+ 209     IF(JMOHEP(2,QHEP).NE.0) THEN
+           IF(JDAHEP(2,JMOHEP(2,QHEP)).EQ.QHEP.AND.
+     &        JMOHEP(2,QHEP).NE.QHEP) THEN
+              IF(JMOHEP(2,QHEP).GE.JC.AND.JMOHEP(2,QHEP).LE.JD) THEN
+                QHEP = JMOHEP(2,QHEP)
+                NCOUNT = NCOUNT+1
+                IF(NCOUNT.LT.NHEP) GOTO 209
+              ENDIF
+           ENDIF
+         ENDIF
+        IF(QHEP.NE.0) COLP=QHEP
+        IF(JDAHEP(2,QHEP).EQ.0.AND.IHEP.NE.6) THEN
+          IDM2= IDHW(QHEP)
+          IF(FLA(IHEP).AND.FLA(QHEP).OR.
+     &       ((AFLA(IHEP).OR.ID.EQ.13.OR.ID.EQ.449).AND.
+     &        (AFLA(QHEP).OR.IDM2.EQ.13.OR.IDM2.EQ.449)))
+     &        JDAHEP(2,QHEP)=IHEP
+        ENDIF
+        ELSE
+         QHEP = JD+1
+ 220     QHEP = QHEP-1
+         IF(IDHEP(QHEP).EQ.0) GOTO 220
+         IF(IDHW(QHEP).EQ.59) THEN
+           IF(JC.EQ.JD.AND.IDHW(JMOHEP(1,QHEP)).EQ.59) THEN
+             COLP = IHEP
+             RETURN
+           ELSE
+             GOTO 220
+           ENDIF
+         ENDIF
+          NCOUNT = 0
+ 219       IF(JDAHEP(2,QHEP).NE.0) THEN
+            IF(JMOHEP(2,JDAHEP(2,QHEP)).EQ.QHEP) THEN
+              IF(JDAHEP(2,QHEP).GE.JC.AND.JDAHEP(2,QHEP).LE.JD) THEN
+                QHEP = JDAHEP(2,QHEP)
+                NCOUNT = NCOUNT+1
+                IF(NCOUNT.LT.200) GOTO 219
+              ENDIF
+            ENDIF
+          ENDIF
+        IF(QHEP.NE.0) COLP=QHEP
+        IDM2 = IDHW(QHEP)
+        IF(JDAHEP(2,QHEP).EQ.0.AND.
+     &     (((AFLA(ID).OR.ID.EQ.13).AND.(AFLA(IDM2).OR.IDM2.EQ.13)).OR.
+     &     (FLA(ID).AND.FLA(IDM2)))) JDAHEP(2,QHEP)=IHEP
+        ENDIF
+       ENDIF
+      ENDIF
+      END
+CDECK  ID>, HWBSPA.
+*CMZ :-        -26/04/91  14.26.44  by  Federico Carminati
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBSPA
+C-----------------------------------------------------------------------
+C     Constructs time-like 4-momenta & production vertices in space-like
+C     jet started by parton no.2 interference partner 1 and spin density
+C     DECPAR(2). RHOPAR(2) gives the jet spin density matrix.
+C     See I.G. Knowles, Comp. Phys. Comm. 58 (90) 271.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,DMIN,PT,EIKON,EISCR,EINUM,EIDEN1,EIDEN2,
+     & WT,SPIN,Z1,Z2,TR,PRMAX,CX,SX,CAZ,ROHEP(3),RMAT(3,3),ZERO2(2)
+      INTEGER JPAR,KPAR,LPAR,MPAR
+      LOGICAL EICOR
+      EXTERNAL HWR
+      DATA ZERO2,DMIN/ZERO,ZERO,1.D-15/
+      IF (IERROR.NE.0) RETURN
+      JPAR=2
+      KPAR=1
+      IF (NPAR.EQ.2) THEN
+         CALL HWVZRO(2,RHOPAR(1,2))
+         RETURN
+      ENDIF
+C Generate azimuthal angle of JPAR's branching using an M-function
+C     Find the daughters of JPAR, with LPAR time-like
+  10  LPAR=JDAPAR(1,JPAR)
+      IF (TMPAR(LPAR)) THEN
+         MPAR=LPAR+1
+      ELSE
+         MPAR=LPAR
+         LPAR=MPAR+1
+      ENDIF
+C Soft correlations
+      CALL HWUROT(PPAR(1,JPAR), ONE,ZERO,RMAT)
+      CALL HWUROF(RMAT,PPAR(1,KPAR),ROHEP)
+      PT=MAX(SQRT(ROHEP(1)*ROHEP(1)+ROHEP(2)*ROHEP(2)),DMIN)
+      EIKON=1.
+      EICOR=AZSOFT.AND.IDPAR(LPAR).EQ.13
+      IF (EICOR) THEN
+         EISCR=1.-PPAR(5,MPAR)*PPAR(5,MPAR)/(MIN(PPAR(2,LPAR),
+     &   PPAR(2,MPAR))*PPAR(4,MPAR)*PPAR(4,MPAR))
+         EINUM=PPAR(4,KPAR)*PPAR(4,LPAR)*ABS(PPAR(2,LPAR)-PPAR(2,MPAR))
+         EIDEN1=PPAR(4,KPAR)*PPAR(4,LPAR)-ROHEP(3)*PPAR(3,LPAR)
+         EIDEN2=PT*ABS(PPAR(1,LPAR))
+         EIKON=MAX(EISCR+EINUM/MAX(EIDEN1-EIDEN2,DMIN),ZERO)
+      ENDIF
+C Spin correlations
+      WT=0.
+      SPIN=1.
+      IF (AZSPIN.AND.IDPAR(JPAR).EQ.13) THEN
+         Z1=PPAR(4,JPAR)/PPAR(4,MPAR)
+         Z2=1.-Z1
+         IF (IDPAR(MPAR).EQ.13) THEN
+            TR=Z1/Z2+Z2/Z1+Z1*Z2
+         ELSEIF (IDPAR(MPAR).LT.13) THEN
+            TR=(Z1*Z1+Z2*Z2)/2.
+         ENDIF
+         WT=Z2/(Z1*TR)
+      ENDIF
+C Assign the azimuthal angle
+      PRMAX=(1.+ABS(WT))*EIKON
+  50  CALL HWRAZM( ONE,CX,SX)
+      CALL HWUROT(PPAR(1,JPAR),CX,SX,RMAT)
+C Determine the angle between the branching planes
+      CALL HWUROF(RMAT,PPAR(1,KPAR),ROHEP)
+      CAZ=ROHEP(1)/PT
+      PHIPAR(1,JPAR)=2.*CAZ*CAZ-1.
+      PHIPAR(2,JPAR)=2.*CAZ*ROHEP(2)/PT
+      IF (EICOR) EIKON=MAX(EISCR+EINUM/MAX(EIDEN1-EIDEN2*CAZ,DMIN),ZERO)
+      IF (AZSPIN) SPIN=1.+WT*(DECPAR(1,JPAR)*PHIPAR(1,JPAR)
+     &                       +DECPAR(2,JPAR)*PHIPAR(2,JPAR))
+      IF (SPIN*EIKON.LT.HWR()*PRMAX) GOTO 50
+C Construct full 4-momentum of LPAR, sum P-trans of MPAR
+      PPAR(2,LPAR)=0.
+      PPAR(2,MPAR)=0.
+      CALL HWUROB(RMAT,PPAR(1,LPAR),PPAR(1,LPAR))
+      CALL HWVDIF(2,PPAR(1,2),PPAR(1,LPAR),PPAR(1,2))
+C Test for end of space-like branches
+      IF (JDAPAR(1,MPAR).EQ.0) GOTO 60
+C     Generate new Decay matrix
+      CALL HWBAZF(MPAR,JPAR,ZERO2,DECPAR(1,JPAR),
+     &            PHIPAR(1,JPAR),DECPAR(1,MPAR))
+C     Advance along the space-like branch
+      JPAR=MPAR
+      KPAR=LPAR
+      GOTO 10
+C Retreat along space-like line
+C     Assign initial spin density matrix
+  60  CALL HWVEQU(2,ZERO2,RHOPAR(1,MPAR))
+      CALL HWUMAS(PPAR(1,2))
+      CALL HWVZRO(4,VPAR(1,MPAR))
+  70  CALL HWVEQU(4,VPAR(1,MPAR),VPAR(1,LPAR))
+      IF (MPAR.EQ.2) RETURN
+C Construct spin density matrix for time-like branch
+      CALL HWBAZF(MPAR,JPAR,RHOPAR(1,MPAR),PHIPAR(1,JPAR),
+     &                      DECPAR(1,JPAR),RHOPAR(1,LPAR))
+C Evolve time-like side branch
+      CALL HWBTIM(LPAR,MPAR)
+C Construct spin density matrix for space-like branch
+      CALL HWBAZF(MPAR,JPAR,PHIPAR(1,JPAR),RHOPAR(1,MPAR),
+     &                      DECPAR(1,LPAR),RHOPAR(1,JPAR))
+C Assign production vertex to J
+      CALL HWVDIF(4,PPAR(1,MPAR),PPAR(1,LPAR),PPAR(1,JPAR))
+      CALL HWUDKL(IDPAR(JPAR),PPAR(1,JPAR),VPAR(1,JPAR))
+      CALL HWVSUM(4,VPAR(1,MPAR),VPAR(1,JPAR),VPAR(1,JPAR))
+C Find parent and partner of MPAR
+      MPAR=JPAR
+      JPAR=JMOPAR(1,MPAR)
+      LPAR=MPAR+1
+      IF (JMOPAR(1,LPAR).NE.JPAR) LPAR=MPAR-1
+      GOTO 70
+      END
+CDECK  ID>, HWBSPN.
+*CMZ :-        -26/04/91  11.11.54  by  Bryan Webber
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBSPN
+C-----------------------------------------------------------------------
+C     Constructs appropriate spin density/decay matrix for parton
+C     in hard subprocess, othwise zero. Assignments based upon
+C     Comp. Phys. Comm. 58 (1990) 271.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION C,V12,V23,V13,TR,C1,C2,C3,R1(2),R2(2)
+      INTEGER IST
+      SAVE R1,R2,V12
+      IF (IERROR.NE.0) RETURN
+      IST=MOD(ISTHEP(NEVPAR),10)
+C Assumed partons processed in the order IST=1,2,3,4
+      IF (IPROC.GE.100.AND.IPROC.LE.116) THEN
+C  An e+e- ---> qqbar g event
+         IF (IDPAR(2).EQ.13) THEN
+            RHOPAR(1,2)=GPOLN
+            RHOPAR(2,2)=0.
+            RETURN
+         ENDIF
+      ELSEIF (IPRO.EQ.15.OR.IPRO.EQ.17) THEN
+         IF (IHPRO.EQ. 7.OR.IHPRO.EQ. 8.OR.
+     &       IHPRO.EQ.10.OR.IHPRO.EQ.11.OR.
+     &       IHPRO.EQ.15.OR.IHPRO.EQ.16.OR.
+     &      (IHPRO.GE.21.AND.IHPRO.LE.31)) THEN
+C A hard 2 --- > 2 QCD subprocess involving gluons
+            IF (IST.EQ.2) THEN
+               CALL HWVEQU(2,RHOPAR(1,2),R1(1))
+               C=GCOEF(2)/GCOEF(1)
+               DECPAR(1,2)=C*R1(1)
+               DECPAR(2,2)=C*R1(2)
+               RETURN
+            ELSEIF (IST.EQ.3) THEN
+               CALL HWVEQU(2,RHOPAR(1,2),R2(1))
+               V12=R1(1)*R2(1)+R1(2)*R2(2)
+               TR=1./(GCOEF(1)+GCOEF(2)*V12)
+               RHOPAR(1,2)= (GCOEF(3)*R1(1)+GCOEF(4)*R2(1))*TR
+               RHOPAR(2,2)=-(GCOEF(3)*R1(2)+GCOEF(4)*R2(2))*TR
+               RETURN
+            ELSEIF (IST.EQ.4) THEN
+               V13=R1(1)*DECPAR(1,2)+R1(2)*DECPAR(2,2)
+               V23=R2(1)*DECPAR(1,2)+R2(2)*DECPAR(2,2)
+               TR=1./(GCOEF(1)+GCOEF(2)*V12+GCOEF(3)*V13+GCOEF(4)*V23)
+               C1=(GCOEF(2)+GCOEF(5))*TR
+               C2=(GCOEF(3)+GCOEF(6))*TR
+               C3=(GCOEF(4)+GCOEF(6))*TR
+               RHOPAR(1,2)=C1*DECPAR(1,2)+C2*R2(1)+C3*R1(1)
+               RHOPAR(2,2)=C1*DECPAR(2,2)-C2*R1(2)-C3*R2(2)
+               RETURN
+            ENDIF
+         ENDIF
+      ELSEIF (IPRO.EQ.16) THEN
+C A gluon fusion ---> Higgs event
+         IF (IST.EQ.2) THEN
+            DECPAR(1,2)=RHOPAR(1,2)
+            DECPAR(2,2)=-RHOPAR(2,2)
+            RETURN
+         ENDIF
+      ENDIF
+      CALL HWVZRO(2,RHOPAR(1,2))
+      CALL HWVZRO(2,DECPAR(1,2))
+      END
+CDECK  ID>, HWBSU1.
+*CMZ :-        -13/07/92  20.15.54  by  Mike Seymour
+*-- Author :    Bryan Webber, modified by Mike Seymour
+C-----------------------------------------------------------------------
+      FUNCTION HWBSU1(ZLOG)
+C-----------------------------------------------------------------------
+C     Z TIMES THE INTEGRAND IN EXPONENT OF QUARK SUDAKOV FORM FACTOR.
+C     HWBSU1 IS FOR UPPER PART OF Z INTEGRATION REGION
+C-----------------------------------------------------------------------
+      DOUBLE PRECISION HWBSU1,HWBSUL,Z,ZLOG,U
+      EXTERNAL HWBSUL
+      Z=EXP(ZLOG)
+      U=1.-Z
+      HWBSU1=HWBSUL(Z)*(1.+U*U)
+      END
+CDECK  ID>, HWBSU2.
+*CMZ :-        -13/07/92  20.15.54  by  Mike Seymour
+*-- Author :    Bryan Webber, modified by Mike Seymour
+C-----------------------------------------------------------------------
+      FUNCTION HWBSU2(Z)
+C-----------------------------------------------------------------------
+C     INTEGRAND IN EXPONENT OF QUARK SUDAKOV FORM FACTOR.
+C     HWBSU2 IS FOR LOWER PART OF Z INTEGRATION REGION
+C-----------------------------------------------------------------------
+      DOUBLE PRECISION HWBSU2,HWBSUL,Z,U
+      EXTERNAL HWBSUL
+      U=1.-Z
+      HWBSU2=HWBSUL(Z)*(1.+Z*Z)/U
+      END
+CDECK  ID>, HWBSUD.
+*CMZ :-        -14/07/92  13.28.23  by  Mike Seymour
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBSUD
+C-----------------------------------------------------------------------
+C     COMPUTES (OR READS) TABLES OF SUDAKOV FORM FACTORS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWUGAU,HWBVMC,HWBSUG,HWBSU1,HWBSU2,G1,G2,QRAT,
+     & QLAM,POWER,AFAC,QMIN,QFAC,QNOW,ZMIN,ZMAX,Q1,QCOLD,VGOLD,VQOLD,
+     & RMOLD(6),ACOLD,ZLO,ZHI
+      INTEGER IQ,IS,L1,L2,L,LL,I,INOLD,NQOLD,NSOLD,NCOLD,NFOLD,SDOLD
+      EXTERNAL HWUGAU,HWBVMC,HWBSUG,HWBSU1,HWBSU2
+      SAVE NQOLD,NSOLD,NCOLD,NFOLD,SDOLD,QCOLD,VGOLD,VQOLD,RMOLD,ACOLD
+      COMMON/HWSINT/QRAT,QLAM
+      IF (LRSUD.EQ.0) THEN
+        POWER=1./FLOAT(NQEV-1)
+        AFAC=6.*CAFAC/BETAF
+        QMIN=QG+QG
+        QFAC=(1.1*QLIM/QMIN)**POWER
+        SUD(1,1)=1.
+        QEV(1,1)=QMIN
+C--IS=1 FOR GLUON->GLUON+GLUON FORM FACTOR
+        DO 10 IQ=2,NQEV
+        QNOW=QFAC*QEV(IQ-1,1)
+        QLAM=QNOW/QCDL3
+        ZMIN=QG/QNOW
+        QRAT=1./ZMIN
+        G1=0
+        DO 5 I=3,6
+          ZLO=ZMIN
+          ZHI=HALF
+          IF (I.NE.6) ZLO=MAX(ZLO,QG/RMASS(I+1))
+          IF (I.NE.3) ZHI=MIN(ZHI,QG/RMASS(I))
+          IF (ZHI.GT.ZLO) G1=G1+HWUGAU(HWBSUG,LOG(ZLO),LOG(ZHI),ACCUR)
+    5   CONTINUE
+        SUD(IQ,1)=EXP(AFAC*G1)
+   10   QEV(IQ,1)=QNOW
+        AFAC=3.*CFFAC/BETAF
+C--QUARK FORM FACTORS.
+C--IS=2,3,4,5,6,7 FOR U/D,S,C,B,T,V
+        DO 15 IS=2,NSUD
+        Q1=HWBVMC(IS)
+        IF (IS.EQ.7) Q1=HWBVMC(209)
+        QMIN=Q1+QG
+        IF (QMIN.GT.QLIM) GOTO 15
+        QFAC=(1.1*QLIM/QMIN)**POWER
+        SUD(1,IS)=1.
+        QEV(1,IS)=QMIN
+        DO 14 IQ=2,NQEV
+        QNOW=QFAC*QEV(IQ-1,IS)
+        QLAM=QNOW/QCDL3
+        ZMIN=QG/QNOW
+        QRAT=1./ZMIN
+        ZMAX=QG/QMIN
+        G1=0
+        DO 12 I=3,6
+          ZLO=ZMIN
+          ZHI=ZMAX
+          IF (I.NE.6) ZLO=MAX(ZLO,QG/RMASS(I+1))
+          IF (I.NE.3) ZHI=MIN(ZHI,QG/RMASS(I))
+          IF (ZHI.GT.ZLO) G1=G1+HWUGAU(HWBSU1,LOG(ZLO),LOG(ZHI),ACCUR)
+   12   CONTINUE
+        ZMIN=Q1/QNOW
+        QRAT=1./ZMIN
+        ZMAX=Q1/QMIN
+        G2=0
+        DO 13 I=3,6
+          ZLO=ZMIN
+          ZHI=ZMAX
+          IF (I.NE.6) ZLO=MAX(ZLO,Q1/RMASS(I+1))
+          IF (I.NE.3) ZHI=MIN(ZHI,Q1/RMASS(I))
+          IF (ZHI.GT.ZLO) G2=G2+HWUGAU(HWBSU2,ZLO,ZHI,ACCUR)
+   13   CONTINUE
+        SUD(IQ,IS)=EXP(AFAC*(G1+G2))
+   14   QEV(IQ,IS)=QNOW
+   15   CONTINUE
+        QCOLD=QCDLAM
+        VGOLD=VGCUT
+        VQOLD=VQCUT
+        ACOLD=ACCUR
+        INOLD=INTER
+        NQOLD=NQEV
+        NSOLD=NSUD
+        NCOLD=NCOLO
+        NFOLD=NFLAV
+        SDOLD=SUDORD
+        DO 16 IS=1,NSUD
+   16   RMOLD(IS)=RMASS(IS)
+      ELSE
+        IF (LRSUD.GT.0) THEN
+          IF (IPRINT.NE.0) WRITE (6,17) LRSUD
+   17     FORMAT(10X,'READING SUDAKOV TABLE ON UNIT',I4)
+          OPEN(UNIT=LRSUD,FORM='UNFORMATTED',STATUS='UNKNOWN')
+          READ(UNIT=LRSUD) QCOLD,VGOLD,VQOLD,RMOLD,
+     &       ACOLD,QEV,SUD,INOLD,NQOLD,NSOLD,NCOLD,NFOLD,SDOLD
+          CLOSE(UNIT=LRSUD)
+        ENDIF
+C---CHECK THAT RELEVANT PARAMETERS ARE UNCHANGED
+        IF (QCDLAM.NE.QCOLD) CALL HWWARN('HWBSUD',501,*999)
+        IF (VGCUT .NE.VGOLD) CALL HWWARN('HWBSUD',502,*999)
+        IF (VQCUT .NE.VQOLD) CALL HWWARN('HWBSUD',503,*999)
+        IF (ACCUR .NE.ACOLD) CALL HWWARN('HWBSUD',504,*999)
+        IF (INTER .NE.INOLD) CALL HWWARN('HWBSUD',505,*999)
+        IF (NQEV  .NE.NQOLD) CALL HWWARN('HWBSUD',506,*999)
+        IF (NSUD  .NE.NSOLD) CALL HWWARN('HWBSUD',507,*999)
+        IF (NCOLO .NE.NCOLD) CALL HWWARN('HWBSUD',508,*999)
+        IF (NFLAV .NE.NFOLD) CALL HWWARN('HWBSUD',509,*999)
+        IF (SUDORD.NE.SDOLD) CALL HWWARN('HWBSUD',510,*999)
+C---CHECK MASSES AND THAT TABLES ARE BIG ENOUGH FOR THIS RUN
+        DO 18 IS=1,NSUD
+          IF (RMASS(IS).NE.RMOLD(IS))
+     &      CALL HWWARN('HWBSUD',510+IS,*999)
+          IF (QEV(NQEV,IS).LT.QLIM.AND.HWBVMC(IS)+QG.LT.QLIM)
+     &      CALL HWWARN('HWBSUD',500,*999)
+   18   CONTINUE
+      ENDIF
+      IF (LWSUD.GT.0) THEN
+        IF (IPRINT.NE.0) WRITE (6,19) LWSUD
+   19   FORMAT(10X,'WRITING SUDAKOV TABLE ON UNIT',I4)
+        OPEN (UNIT=LWSUD,FORM='UNFORMATTED',STATUS='UNKNOWN')
+        WRITE(UNIT=LWSUD)  QCDLAM,VGCUT,VQCUT,(RMASS(I),I=1,6),
+     &     ACCUR,QEV,SUD,INTER,NQEV,NSUD,NCOLO,NFLAV,SUDORD
+        CLOSE(UNIT=LWSUD)
+      ENDIF
+      IF (IPRINT.GT.2) THEN
+C--PRINT EXTRACTS FROM TABLES OF FORM FACTORS
+        DO 40 IS=1,NSUD
+        WRITE(6,20) IS,NQEV
+   20   FORMAT(1H1//10X,'EXTRACT FROM TABLE OF SUDAKOV FORM FACTOR NO.',
+     &  I2,' (',I5,' ACTUAL ENTRIES)'//10X,'SUD IS PROBABILITY THAT',
+     &  ' PARTON WITH GIVEN UPPER LIMIT ON Q WILL REACH THRESHOLD',
+     &  ' WITHOUT BRANCHING'///2X,8('      Q     SUD ')/)
+        L2=NQEV/8
+        L1=L2/32
+        IF (L1.LT.1) L1=1
+        DO 40 L=L1,L2,L1
+        LL=L+7*L2
+        WRITE(6,30) (QEV(I,IS),SUD(I,IS),I=L,LL,L2)
+   30   FORMAT(2X,8(F9.2,F7.4))
+   40   CONTINUE
+        WRITE(6,50)
+   50   FORMAT(1H1)
+      ENDIF
+  999 END
+CDECK  ID>, HWBSUG.
+*CMZ :-        -13/07/92  20.15.54  by  Mike Seymour
+*-- Author :    Bryan Webber, modified by Mike Seymour
+C-----------------------------------------------------------------------
+      FUNCTION HWBSUG(ZLOG)
+C-----------------------------------------------------------------------
+C     Z TIMES INTEGRAND IN EXPONENT OF GLUON SUDAKOV FORM FACTOR
+C-----------------------------------------------------------------------
+      DOUBLE PRECISION HWBSUG,HWBSUL,Z,ZLOG,W
+      EXTERNAL HWBSUL
+      Z=EXP(ZLOG)
+      W=Z*(1.-Z)
+      HWBSUG=HWBSUL(Z)*(W-2.+1./W)*Z
+      END
+CDECK  ID>, HWBSUL.
+*CMZ :-        -13/07/92  20.15.54  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      FUNCTION HWBSUL(Z)
+C-----------------------------------------------------------------------
+C     LOGARITHMIC PART OF INTEGRAND IN EXPONENT OF SUDAKOV FORM FACTOR.
+C     THE SECOND ORDER ALPHAS CASE COMES FROM CONVERTING INTEGRAL OVER
+C     Q^2 INTO ONE OVER ALPHAS, WITH FLAVOUR THRESHOLDS.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBSUL,HWUALF,Z,QRAT,QLAM,U,AL,BL,QNOW,QMIN,
+     & BET(6),BEP(6),MUMI(6),MUMA(6),ALMI(6),ALMA(6),FINT(6),ALFINT,
+     & MUMIN,MUMAX,ALMIN,ALMAX
+      INTEGER NF
+      LOGICAL FIRST
+      EXTERNAL HWUALF
+      SAVE FIRST,BET,BEP,MUMI,MUMA
+      COMMON/HWSINT/QRAT,QLAM
+      DATA FIRST/.TRUE./
+      ALFINT(AL,BL)=1/BET(NF)*
+     &        LOG(BL/(AL*(1+BEP(NF)*BL))*(1+BEP(NF)*AL))
+      HWBSUL=0
+      U=1.-Z
+      IF (SUDORD.EQ.1) THEN
+        AL=LOG(QRAT*Z)
+        BL=LOG(QLAM*U*Z)
+        HWBSUL=LOG(1.-AL/BL)
+      ELSE
+        IF (FIRST) THEN
+          DO 10 NF=3,6
+            BET(NF)=(11*CAFAC-2*NF)/(12*PIFAC)
+            BEP(NF)=(17*CAFAC**2-(5*CAFAC+3*CFFAC)*NF)/(24*PIFAC**2)
+     &              /BET(NF)
+            IF (NF.EQ.3) THEN
+              MUMI(3)=0
+              ALMI(3)=1D30
+            ELSE
+              MUMI(NF)=RMASS(NF)
+              ALMI(NF)=HWUALF(1,MUMI(NF))
+            ENDIF
+            IF (NF.EQ.6) THEN
+              MUMA(NF)=1D30
+              ALMA(NF)=0
+            ELSE
+              MUMA(NF)=RMASS(NF+1)
+              ALMA(NF)=HWUALF(1,MUMA(NF))
+            ENDIF
+            IF (NF.NE.3.AND.NF.NE.6) FINT(NF)=ALFINT(ALMI(NF),ALMA(NF))
+ 10       CONTINUE
+          FIRST=.FALSE.
+        ENDIF
+        QNOW=QLAM*QCDL3
+        QMIN=QNOW/QRAT
+        MUMIN=  U*QMIN
+        MUMAX=Z*U*QNOW
+        IF (MUMAX.LE.MUMIN) RETURN
+        ALMIN=HWUALF(1,MUMIN)
+        ALMAX=HWUALF(1,MUMAX)
+        NF=3
+ 20     IF (MUMIN.GT.MUMA(NF)) THEN
+          NF=NF+1
+          GOTO 20
+        ENDIF
+        IF (MUMAX.LT.MUMA(NF)) THEN
+          HWBSUL=ALFINT(ALMIN,ALMAX)
+        ELSE
+          HWBSUL=ALFINT(ALMIN,ALMA(NF))
+          NF=NF+1
+ 30       IF (MUMAX.GT.MUMA(NF)) THEN
+            HWBSUL=HWBSUL+FINT(NF)
+            NF=NF+1
+            GOTO 30
+          ENDIF
+          HWBSUL=HWBSUL+ALFINT(ALMI(NF),ALMAX)
+        ENDIF
+        HWBSUL=HWBSUL*BET(5)
+      ENDIF
+      END
+CDECK  ID>, HWBTIM.
+*CMZ :-        -26/04/91  14.27.17  by  Federico Carminati
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBTIM(INITBR,INTERF)
+C-----------------------------------------------------------------------
+C     Constructs full 4-momentum & production vertices in time-like jet
+C     initiated by INITBR, interference partner INTERF and spin density
+C     RHOPAR(INITBR). DECPAR(INITBR) returns jet's spin density matrix.
+C     Includes azimuthal angular correlations between branching planes
+C     due to spin (if AZSPIN) using the algorithm of Knowles & Collins.
+C     Ses Nucl. Phys. B304 (1988) 794 & Comp. Phys. Comm. 58 (1990) 271.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,DMIN,PT,EIKON,EINUM,EIDEN1,EIDEN2,EISCR,
+     & WT,SPIN,Z1,Z2,PRMAX,CAZ,CX,SX,ROHEP(3),RMAT(3,3),ZERO2(2)
+      INTEGER INITBR,INTERF,IPAR,JPAR,KPAR,LPAR,MPAR,NTRY,JOLD
+      LOGICAL EICOR,SWAP
+      EXTERNAL HWR
+      DATA ZERO2,DMIN/ZERO,ZERO,1.D-15/
+      IF (IERROR.NE.0) RETURN
+      JPAR=INITBR
+      KPAR=INTERF
+      IF ((JDAPAR(1,JPAR).NE.0).OR.(IDPAR(JPAR).EQ.13)) GOTO 30
+C No branching, assign decay matrix
+      CALL HWVZRO(2,DECPAR(1,JPAR))
+      RETURN
+C Advance up the leader
+C     Find the parent and partner of J
+  10  IPAR=JMOPAR(1,JPAR)
+      KPAR=JPAR+1
+C Generate new Rho
+      IF (JMOPAR(1,KPAR).EQ.IPAR) THEN
+C        Generate Rho'
+         CALL HWBAZF(IPAR,JPAR,PHIPAR(1,IPAR),RHOPAR(1,IPAR),
+     &                                   ZERO2,RHOPAR(1,JPAR))
+      ELSE
+         KPAR=JPAR-1
+         IF (JMOPAR(1,KPAR).NE.IPAR)
+     &   CALL HWWARN('HWBTIM',100,*999)
+C        Generate Rho''
+         CALL HWBAZF(IPAR,KPAR,RHOPAR(1,IPAR),PHIPAR(1,IPAR),
+     &                         DECPAR(1,KPAR),RHOPAR(1,JPAR))
+      ENDIF
+C Generate azimuthal angle of J's branching
+  30  IF (JDAPAR(1,JPAR).EQ.0) THEN
+C        Final state gluon
+         CALL HWVZRO(2,DECPAR(1,JPAR))
+         IF (JPAR.EQ.INITBR) RETURN
+         GOTO 70
+      ELSE
+C Assign an angle to a branching using an M-function
+C        Find the daughters of J
+         LPAR=JDAPAR(1,JPAR)
+         MPAR=JDAPAR(2,JPAR)
+C Soft correlations
+         CALL HWUROT(PPAR(1,JPAR), ONE,ZERO,RMAT)
+         CALL HWUROF(RMAT,PPAR(1,KPAR),ROHEP)
+         PT=MAX(SQRT(ROHEP(1)*ROHEP(1)+ROHEP(2)*ROHEP(2)),DMIN)
+         EIKON=1.
+         SWAP=.FALSE.
+         EICOR=AZSOFT.AND.((IDPAR(LPAR).EQ.13).OR.(IDPAR(MPAR).EQ.13))
+         IF (EICOR) THEN
+C           Rearrange s.t. LPAR is the (softest) gluon
+            IF (IDPAR(MPAR).EQ.13) THEN
+               IF (IDPAR(LPAR).NE.13.OR.
+     &             PPAR(4,MPAR).LT.PPAR(4,LPAR)) THEN
+                  SWAP=.TRUE.
+                  LPAR=MPAR
+                  MPAR=LPAR-1
+               ENDIF
+            ENDIF
+            EINUM=(PPAR(4,KPAR)*PPAR(4,LPAR))
+     &        *ABS(PPAR(2,LPAR)-PPAR(2,MPAR))
+            EIDEN1=(PPAR(4,KPAR)*PPAR(4,LPAR))-ROHEP(3)*PPAR(3,LPAR)
+            EIDEN2=PT*ABS(PPAR(1,LPAR))
+            EISCR=1.-(PPAR(5,MPAR)/PPAR(4,MPAR))**2
+     &           /MIN(PPAR(2,LPAR),PPAR(2,MPAR))
+            EIKON=EISCR+EINUM/MAX(EIDEN1-EIDEN2,DMIN)
+         ENDIF
+C Spin correlations
+         WT=0.
+         SPIN=1.
+         IF (AZSPIN) THEN
+            Z1=PPAR(4,LPAR)/PPAR(4,JPAR)
+            Z2=1.-Z1
+            IF (IDPAR(JPAR).EQ.13.AND.IDPAR(LPAR).EQ.13) THEN
+               WT=Z1*Z2/(Z1/Z2+Z2/Z1+Z1*Z2)
+            ELSEIF (IDPAR(JPAR).EQ.13.AND.IDPAR(LPAR).LT.13) THEN
+               WT=-2.*Z1*Z2/(Z1*Z1+Z2*Z2)
+            ENDIF
+         ENDIF
+C Assign the azimuthal angle
+         PRMAX=(1.+ABS(WT))*EIKON
+         NTRY=0
+   50    NTRY=NTRY+1
+         IF (NTRY.GT.NBTRY) CALL HWWARN('HWBTIM',101,*999)
+         CALL HWRAZM( ONE,CX,SX)
+         CALL HWUROT(PPAR(1,JPAR),CX,SX,RMAT)
+C Determine the angle between the branching planes
+         CALL HWUROF(RMAT,PPAR(1,KPAR),ROHEP)
+         CAZ=ROHEP(1)/PT
+         PHIPAR(1,JPAR)=2.*CAZ*CAZ-1.
+         PHIPAR(2,JPAR)=2.*CAZ*ROHEP(2)/PT
+         IF (EICOR) EIKON=EISCR+EINUM/MAX(EIDEN1-EIDEN2*CAZ,DMIN)
+         IF (AZSPIN) SPIN=1.+WT*(RHOPAR(1,JPAR)*PHIPAR(1,JPAR)
+     &                          +RHOPAR(2,JPAR)*PHIPAR(2,JPAR))
+         IF (SPIN*EIKON.LT.HWR()*PRMAX) GOTO 50
+C Construct full 4-momentum of L and M
+         JOLD=JPAR
+         IF (SWAP) THEN
+           PPAR(1,LPAR)=-PPAR(1,LPAR)
+           PPAR(1,MPAR)=-PPAR(1,MPAR)
+           JPAR=MPAR
+         ELSE
+           JPAR=LPAR
+         ENDIF
+         PPAR(2,LPAR)=0.
+         CALL HWUROB(RMAT,PPAR(1,LPAR),PPAR(1,LPAR))
+         PPAR(2,MPAR)=0.
+         CALL HWUROB(RMAT,PPAR(1,MPAR),PPAR(1,MPAR))
+C Assign production vertex to L and M
+         CALL HWUDKL(IDPAR(JOLD),PPAR(1,JOLD),VPAR(1,LPAR))
+         CALL HWVSUM(4,VPAR(1,JOLD),VPAR(1,LPAR),VPAR(1,LPAR))
+         CALL HWVEQU(4,VPAR(1,LPAR),VPAR(1,MPAR))
+      ENDIF
+  60  IF (JDAPAR(1,JPAR).NE.0) GOTO 10
+C Assign decay matrix
+      CALL HWVZRO(2,DECPAR(1,JPAR))
+C Backtrack down the leader
+  70  IPAR=JMOPAR(1,JPAR)
+      KPAR=JDAPAR(1,IPAR)
+      IF (KPAR.EQ.JPAR) THEN
+C        Develop the side branch
+         JPAR=JDAPAR(2,IPAR)
+         GOTO 60
+      ELSE
+C        Construct decay matrix
+         CALL HWBAZF(IPAR,KPAR,DECPAR(1,JPAR),DECPAR(1,KPAR),
+     &                         PHIPAR(1,IPAR),DECPAR(1,IPAR))
+      ENDIF
+      IF (IPAR.EQ.INITBR) RETURN
+      JPAR=IPAR
+      GOTO 70
+  999 END
+CDECK  ID>, HWBTOP.
+*CMZ :-        -14/10/99  18.04.56  by  Mike Seymour
+*-- Author :    Gennaro Corcella
+C-----------------------------------------------------------------------
+      SUBROUTINE HWBTOP
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBVMC,HWR,HWUALF,HWUSQR,X(3),W,
+     & X3MIN,X3MAX,X1MIN,X1MAX,QSCALE,GLUFAC,R(3,3),M(3),
+     & E(3),AW,PTSQ,EM,EPS,MASDEP,A,B,C,GAMDEP,LAMBDA,
+     & PW(5),PT(5),PW1(5),CS,SN,EPG,QQ,RR,CC
+      INTEGER ID,ID3,IHEP,KHEP,WHEP,ICMF,K
+      EXTERNAL HWBVMC,HWUALF,HWUSQR,HWR
+      LAMBDA(A,B,C)=(A**2+B**2+C**2-2*A*B-2*B*C-2*C*A)/(4*A)
+C---FIND AN UNTREATED CMF
+      ICMF=0
+      DO 10 IHEP=1,NHEP
+C----FIND A DECAYING TOP QUARK
+ 10     IF (ISTHEP(IHEP).EQ.155.AND.ISTHEP(JDAHEP(1,IHEP)).EQ.113
+     &       .AND.(IDHW(IHEP).EQ.6.OR.IDHW(IHEP).EQ.12))
+     &       ICMF=IHEP
+      IF (ICMF.EQ.0) RETURN
+      EM=PHEP(5,ICMF)
+      X3MIN=2*GCUTME/EM
+C---GENERATE X(1),X(3) ACCORDING TO 1/((1-X(1))*X(3)**2)
+ 100  CONTINUE
+C-----AW=(MW/MT)**2
+      AW=(PHEP(5,JDAHEP(1,ICMF))/EM)**2
+C---CHOOSE X3
+      X3MAX=1-AW
+      X(3)=X3MIN*X3MAX/(X3MIN+(X3MAX-X3MIN)*HWR())
+C--CC, QQ AND RR ARE THE VARIABLE DEFINED IN OUR PAPER
+C--IN ORDER TO SOLVE THE CUBIC EQUATION
+      CC=(1-AW)**2/4
+      QQ=(AW**2-4*(1-X(3))*(2-CC-X(3))-2*AW*(3+2*X(3)))/3
+     &     -((3+2*AW-4*X(3))**2)/9
+      RR=((3+2*AW-4*X(3))*(AW**2-4*(1-X(3))*(2-CC-X(3))
+     &     -2*AW*(3+2*X(3)))-3*(AW*(4-AW)*(2-CC)+(1-CC)
+     &     *(2*(1-X(3))-AW)**2))/6-(ONE/27)*(3+2*AW-4*X(3))**3
+C---CHOOSE X1
+      X1MAX=2*(-QQ**3)**(ONE/6)*COS(ACOS(RR/SQRT(-QQ**3))/3)
+     &     -(3+2*AW-4*X(3))/3
+      X1MIN=1-X(3)+(AW*X(3))/(1-X(3))
+      IF (X1MAX.GE.1.OR.X1MIN.GE.1.OR.X1MAX.LE.X1MIN) GOTO 100
+      X(1)=1-(1-X1MAX)*((1-X1MIN)/(1-X1MAX))**HWR()
+C---CALCULATE WEIGHT
+      W=((1+1/AW-2*AW)*((1-AW)*X(3)-(1-X(1))*(1-X(3))-X(3)**2)
+     &     +(1+1/(2*AW))*X(3)*(X(1)+X(3)-1)**2+2*X(3)**2*(1-X(1)))
+     &     *(1/X3MIN-1/X3MAX)*LOG((1-X1MIN)/(1-X1MAX))
+C---QSCALE=DURHAM-LIKE TRANSVERSE MOMENTUM OF THE GLUON
+      QSCALE=EM*HWUSQR(X(3)*(1-X(1))/(2-X(1)-X(3)-AW))
+C---FACTOR FOR GLUON EMISSION
+      ID=IDHW(JDAHEP(2,ICMF))
+      GLUFAC=0
+      IF (QSCALE.GT.HWBVMC(13)) GLUFAC=CFFAC*HWUALF(1,QSCALE)
+     &     /(PIFAC*(1-AW)*(1-2*AW+1/AW))
+C---IN FRACTION GLUFAC*W OF EVENTS ADD A GLUON
+      IF (GLUFAC*W.GT.HWR()) THEN
+        ID3=13
+      ELSE
+        RETURN
+      ENDIF
+C---CHECK INFRA-RED CUT-OFF FOR GLUON
+      M(1)=PHEP(5,JDAHEP(1,ICMF))
+      M(2)=HWBVMC(ID)
+      M(3)=HWBVMC(ID3)
+      E(1)=HALF*EM*(X(1)+AW+(-M(2)**2-M(3)**2)/EM**2)
+      E(3)=HALF*EM*X(3)
+      E(2)=EM-E(1)-E(3)
+      PTSQ=-LAMBDA(E(1)**2-M(1)**2,E(3)**2-M(3)**2,
+     &     E(2)**2-M(2)**2)
+      IF (PTSQ.LE.0.OR.E(1).LE.M(1).OR.E(2).LE.M(2).OR.E(3).LE.M(3))
+     $     RETURN
+C---CALCULATE MASS-DEPENDENT SUPPRESSION
+      EPS=(RMASS(ID)/EM)**2
+      EPG=(RMASS(ID3)/EM)**2
+      GAMDEP=(1-AW)*(1+1/AW-2*AW)/(SQRT(1+AW**2+EPS**2
+     &     -2*AW-2*EPS-2*AW*EPS)*(1+EPS+(1-EPS)**2/AW-2*AW))
+      MASDEP=GAMDEP/(1-X(1))*((1+EPS+(1-EPS)**2/AW-2*AW)
+     &     *((1-AW+EPS)*X(3)*(1-X(1))-(1-X(1))**2*(1-X(3))
+     &     -X(3)**2*(1-X(1)+EPS))+(1+(1+EPS)/(2*AW))*X(3)
+     &     *(1-X(1))*(X(1)+X(3)-1)**2+2*X(3)**2*(1-X(1))**2)
+      IF (MASDEP.LT.HWR()*((1+1/AW-2*AW)*((1-AW)*X(3)
+     &     -(1-X(1))*(1-X(3))-X(3)**2)+(1+1/(2*AW))*X(3)
+     &     *(X(1)+X(3)-1)**2+2*X(3)**2*(1-X(1)))) RETURN
+C---STORE OLD MOMENTA
+c---PT = TOP MOMENTUM, PW= W MOMENTUM
+      CALL HWVEQU(5,PHEP(1,ICMF),PT)
+      CALL HWVEQU(5,PHEP(1,JDAHEP(1,ICMF)),PW)
+C--------GET THE NON-EMITTING PARTON CMF DIRECTION
+      CALL HWULOF(PHEP(1,ICMF),PW,PW)
+      CALL HWRAZM(ONE,CS,SN)
+      CALL HWUROT(PW,CS,SN,R)
+      CALL HWUROF(R,PW,PW)
+      CALL HWUMAS(PW)
+C---REORDER ENTRIES: IHEP=EMITTER,  KHEP=EMITTED
+      NHEP=NHEP+1
+      IHEP=JDAHEP(2,ICMF)
+      WHEP=JDAHEP(1,ICMF)
+      KHEP=NHEP
+C---SET UP MOMENTA IN TOP REST FRAME
+      PHEP(1,ICMF)=0
+      PHEP(2,ICMF)=0
+      PHEP(3,ICMF)=0
+      PHEP(4,ICMF)=EM
+      PHEP(5,ICMF)=EM
+      PHEP(4,IHEP)=HALF*EM*(2-X(1)-X(3)+EPS-AW+EPG)
+      PHEP(4,KHEP)=HALF*EM*X(3)
+      PHEP(5,IHEP)=RMASS(ID)
+      PHEP(5,KHEP)=RMASS(ID3)
+      PHEP(3,KHEP)=HALF*EM*((X(1)+AW-EPS-EPG)*X(3)-2*(1+EPS-AW
+     $     -EPG-(2+EPS+EPG-AW-X(1)-X(3))))/HWUSQR((X(1)+AW
+     $     -EPS-EPG)**2-4*AW)
+      PHEP(3,IHEP)=-PHEP(3,KHEP)-HALF*EM
+     $     *HWUSQR((X(1)+AW-EPS-EPG)**2-4*AW)
+      PHEP(2,IHEP)=0
+      PHEP(1,KHEP)=HWUSQR(PHEP(4,KHEP)**2-PHEP(5,KHEP)**2
+     $     -PHEP(3,KHEP)**2)
+      PHEP(1,IHEP)=-PHEP(1,KHEP)
+      PHEP(2,KHEP)=0
+      CALL HWVSUM(4,PHEP(1,IHEP),PHEP(1,KHEP),PW1)
+      CALL HWVDIF(4,PHEP(1,ICMF),PW1,PW1)
+      CALL HWUMAS(PW1)
+      DO K=1,5
+        PHEP(K,WHEP)=PW1(K)
+      ENDDO
+C---ORIENT IN CMF, THEN BOOST TO LAB
+      CALL HWUROB(R,PHEP(1,ICMF),PHEP(1,ICMF))
+      CALL HWUROB(R,PHEP(1,IHEP),PHEP(1,IHEP))
+      CALL HWUROB(R,PHEP(1,WHEP),PHEP(1,WHEP))
+      CALL HWUROB(R,PHEP(1,KHEP),PHEP(1,KHEP))
+      CALL HWULOB(PT,PHEP(1,IHEP),PHEP(1,IHEP))
+      CALL HWULOB(PT,PHEP(1,KHEP),PHEP(1,KHEP))
+      CALL HWULOB(PT,PHEP(1,ICMF),PHEP(1,ICMF))
+      CALL HWULOB(PT,PHEP(1,WHEP),PHEP(1,WHEP))
+C---STATUS AND COLOUR CONNECTION
+      ISTHEP(KHEP)=114
+      IDHW(KHEP)=ID3
+      IDHEP(KHEP)=IDPDG(ID3)
+      JDAHEP(2,ICMF)=KHEP
+      JMOHEP(1,KHEP)=ICMF
+      JMOHEP(1,IHEP)=ICMF
+      JDAHEP(1,KHEP)=0
+      JMOHEP(2,IHEP)=ICMF
+      JDAHEP(2,IHEP)=KHEP
+      JMOHEP(2,KHEP)=IHEP
+      JDAHEP(2,KHEP)=ICMF
+ 999  END
+CDECK  ID>, HWBVMC.
+*CMZ :-        -26/04/91  11.11.54  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      FUNCTION HWBVMC(ID)
+C-----------------------------------------------------------------------
+C     VIRTUAL MASS CUTOFF FOR PARTON TYPE ID
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWBVMC
+      INTEGER ID
+      IF (ID.EQ.13) THEN
+        HWBVMC=RMASS(ID)+VGCUT
+      ELSEIF (ID.LT.13) THEN
+        HWBVMC=RMASS(ID)+VQCUT
+      ELSEIF (ID.EQ.59) THEN
+        HWBVMC=RMASS(ID)+VPCUT
+      ELSE
+        HWBVMC=RMASS(ID)
+      ENDIF
+      END
+CDECK  ID>, HWCBCT.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCBCT(JHEP,KHEP,THEP,PCL,SPLIT)
+C-----------------------------------------------------------------------
+C  Subroutine to split a baryonic cluster containing two heavy quarks
+C  Based on HWCCUT
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWUPCM,HWR,HWVDOT,EMC,QM1,QM2,QM3,QM4,
+     &                 PXY,PCX,PCY,RCM,PCL(5),AX(5),PA(5),PB(5),PC(5),
+     &                 VCLUS(4),DQM,EMX,EMY,SKAPPA,RKAPPA,VTMP(4),
+     &                 DELTM,PDIQUK(5),AY(5)
+      INTEGER HWRINT,JHEP,KHEP,LHEP,MHEP,THEP,ID1,ID2,ID3,ID4,NTRY,
+     &        NTRYMX,J,IB
+      LOGICAL SPLIT
+      EXTERNAL HWUPCM,HWR,HWVDOT
+      PARAMETER(SKAPPA=1.,NTRYMX=100)
+      IF(IERROR.NE.0) RETURN
+      EMC=PCL(5)
+      ID1=IDHW(JHEP)
+      ID2=IDHW(KHEP)
+      ID3=IDHW(THEP)
+      QM1=RMASS(ID1)
+      QM2=RMASS(ID2)
+      QM3=RMASS(ID3)
+      SPLIT = .FALSE.
+      NTRY = 0
+C Decide if cluster contains a b-(anti)quark
+      IF (ID1.EQ.5.OR.ID1.EQ.11.OR.ID2.EQ.5.OR.ID2.EQ.11.OR.
+     &    ID3.EQ.5.OR.ID3.EQ.11) THEN
+        IB=2
+      ELSE
+        IB=1
+      ENDIF
+C-- Set the positon of the cluster to be that of the heavy quark
+      CALL HWVEQU(4,VHEP(1,THEP),VCLUS)
+C--SPLIT THE BARYONIC CLUSTER INTO A HEAVY FLAVOUR MESON AND A HEAVY
+C--FLAVOUR BARYON
+      PXY=EMC-QM1-QM2-QM3
+ 20   NTRY=NTRY+1
+      IF(NTRY.GT.NTRYMX) RETURN
+ 30   EMX=QM1+QM2+PXY*HWR()**PSPLT(IB)
+      EMY=    QM3+PXY*HWR()**PSPLT(IB)
+      IF(EMX+EMY.GE.EMC) GOTO 30
+C--PULL A LIGHT QUARK PAIR OUT OF THE VACUUM
+ 40   ID4=HWRINT(1,3)
+      IF(QWT(ID4).LT.HWR()) GOTO 40
+      QM4=RMASS(ID4)
+C--Now combine particles 3 & 4 into a diquark
+C--If three also heavy this diquark doesn't exist in HERWIG
+C--just assume mass is sum of quark masses,as for other diquarks
+      DQM=QM3+QM4
+C--Now obtain the masses for the cluster splitting
+      PCX=HWUPCM(EMX,QM1,DQM)
+      IF(PCX.LT.ZERO) GOTO 20
+      PCY=HWUPCM(EMY,QM2,QM4)
+      IF(PCY.LT.ZERO) GOTO 20
+      SPLIT=.TRUE.
+C--Now we've decided which light quark to pull out of the vacuum
+C--Find the direction of the second heavy quark
+      CALL HWULOF(PCL,PHEP(1,THEP),AX)
+      RCM=1./SQRT(HWVDOT(3,AX,AX))
+      CALL HWVSCA(3,RCM,AX,AX)
+C--Construct the new CoM momenta(collinear)
+      PXY=HWUPCM(EMC,EMX,EMY)
+      CALL HWVSCA(3,PXY,AX,PC)
+C--pc is momenta of Y cluster along 2nd quark dirn in cluster frame
+      PC(4)=SQRT(PXY**2+EMY**2)
+      PC(5)=EMY
+C--pa is momenta of 2nd quark in Y frame
+      CALL HWVSCA(3,PCY,AX,PA)
+      PA(4)=SQRT(PCY**2+QM3**2)
+      PA(5)=QM3
+C--pb is momenta of 2nd quark in cluster frame,pa now momenta of antiquark
+      CALL HWULOB(PC,PA,PB)
+      CALL HWVDIF(4,PC,PB,PA)
+      PA(5)=QM4
+      LHEP=NHEP+1
+      MHEP=NHEP+2
+C--boost these momenta back to lab frame
+      CALL HWULOB(PCL,PB,PHEP(1,THEP))
+      CALL HWULOB(PCL,PA,PHEP(1,MHEP))
+C--pc now becomes momenta of X cluster in cluster frame
+      CALL HWVSCA(3,-ONE,PC,PC)
+      PC(4)=EMC-PC(4)
+      PC(5)=EMX
+C--find the dirn of the 1st heavy quark in the X frame
+C--transform to cluster frame
+      CALL HWULOF(PCL,PHEP(1,JHEP),AY)
+C--transform to X-frame
+      CALL HWULOF(PC,AY,AY)
+      RCM=1./SQRT(HWVDOT(3,AY,AY))
+      CALL HWVSCA(3,RCM,AY,AY)
+C--pa now momenta of 1st havy quark along this dirn
+      CALL HWVSCA(3,PCX,AY,PA)
+      PA(4)=SQRT(PCX**2+QM1**2)
+      PA(5)=QM1
+C--pb now momenta of 1st heavy quark in cluster frame then to lab
+      CALL HWULOB(PC,PA,PB)
+      CALL HWULOB(PCL,PB,PHEP(1,JHEP))
+C--now find the diquark momenta by momentum conservation
+      DO 50 J=1,4
+ 50   PDIQUK(J)=PCL(J)-PHEP(J,THEP)-PHEP(J,MHEP)-PHEP(J,JHEP)
+      PDIQUK(5)=DQM
+C--Now obtain the quark momenta from the diquark
+      DO 60 J=1,3
+ 60   PA(J) = 0
+      PA(4) = QM2
+      PA(5) = QM2
+      CALL HWULOB(PDIQUK,PA,PHEP(1,KHEP))
+      CALL HWVDIF(4,PDIQUK,PHEP(1,KHEP),PHEP(1,LHEP))
+C--Construct new vertex positions
+      RKAPPA=GEV2MM/SKAPPA
+      CALL HWVSCA(3,RKAPPA,AX,AX)
+      DELTM=(EMX-EMY)*(EMX+EMY)/(TWO*EMC)
+      CALL HWVSCA(3,DELTM,AX,VTMP)
+      VTMP(4)=(HALF*EMC-PXY)*RKAPPA
+      CALL HWULB4(PCL,VTMP,VTMP)
+      CALL HWVSUM(4,VTMP,VCLUS,VHEP(1,LHEP))
+      CALL HWVEQU(4,VHEP(1,LHEP),VHEP(1,MHEP))
+C--Relabel the colours of the quarks
+      IDHEP(LHEP) = IDPDG(ID4)
+      IDHEP(MHEP) = IDPDG(ID4)
+      IF(IDHEP(JHEP).GT.0) THEN
+        IDHW(LHEP)  = ID4+6
+        IDHEP(LHEP) = -IDHEP(LHEP)
+        IDHW(MHEP)  = ID4
+        JDAHEP(2,LHEP) = JHEP
+        JMOHEP(2,LHEP) = MHEP
+        JMOHEP(2,MHEP) = JMOHEP(2,JHEP)
+        JDAHEP(2,MHEP) = LHEP
+        JMOHEP(2,JHEP) = LHEP
+      ELSE
+        IDHW(LHEP)  = ID4
+        IDHW(MHEP)  = ID4+6
+        IDHEP(MHEP) = -IDHEP(MHEP)
+        JMOHEP(2,LHEP) = JHEP
+        JDAHEP(2,MHEP) = JDAHEP(2,JHEP)
+        JDAHEP(2,LHEP) = MHEP
+        JMOHEP(2,MHEP) = LHEP
+        JDAHEP(2,JHEP) = LHEP
+      ENDIF
+      ISTHEP(LHEP) = 151
+      ISTHEP(MHEP) = 151
+      JMOHEP(1,LHEP) = JMOHEP(1,KHEP)
+      JDAHEP(1,LHEP) = 0
+      JMOHEP(1,MHEP) = JMOHEP(1,JHEP)
+      JDAHEP(1,MHEP) = 0
+      NHEP = NHEP+2
+ 999  END
+CDECK  ID>, HWCBVI.
+*CMZ :-
+*-- Author :    Mark Gibbs  modified by Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCBVI
+C-----------------------------------------------------------------------
+C FINDS UNPAIRED PARTONS AFTER BARYON-NUMBER VIOLATION
+C  MODIFIED FOR RPARITY VIOLATING SUSY
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      COMMON/HWBVIC/NBV,IBV(18)
+      DOUBLE PRECISION HWR,PDQ(5)
+      INTEGER NBV,IBV,JBV,KBV,LBV,IHEP,IP1,IP2,IP3,JP1,JP2,JP3,
+     & HWCBVT,NBR,MBV,IQ1,IQ2,IQ3,ID1,ID2,IDQ,IDIQK(3,3)
+      LOGICAL SPLIT,DUNBV(18)
+      DATA IDIQK/111,110,113,110,109,112,113,112,114/
+C---Check for errors
+      IF (IERROR.NE.0)  RETURN
+C---Correct colour connections are gluon splitting
+      CALL HWCCCC
+C---Reset bvi clustering flag
+      HVFCEN = .FALSE.
+C---LIST PARTONS WITH WRONG COLOUR PARTNERS-QUARKS ONLY
+    5 NBV=0
+      DO 10 IHEP=1,NHEP
+      IF (ISTHEP(IHEP).GT.149.AND.ISTHEP(IHEP).LT.155) THEN
+        IF (QORQQB(IDHW(IHEP))) THEN
+          IF (.NOT.QORQQB(IDHW(JMOHEP(2,IHEP))).
+     &        AND.JMOHEP(2,IHEP).GT.6) GOTO 10
+        ELSE
+C---Extra check for Gamma's
+          IF (IDHW(IHEP).EQ.59) GO TO 10
+C---End of bug fix.
+          IF (QORQQB(IDHW(JDAHEP(2,IHEP)))) GO TO 10
+          GO TO 10
+        ENDIF
+        IF(JMOHEP(2,IHEP).LT.6.AND.
+     &     .NOT.QBORQQ(IDHW(JMOHEP(2,IHEP)))) GOTO 10
+C--new for hard process
+        NBV=NBV+1
+        IF (NBV.GT.18) CALL HWWARN('HWCBVI',100,*999)
+        IBV(NBV)=IHEP
+        DUNBV(NBV)=.FALSE.
+      ENDIF
+   10 CONTINUE
+C--NOW FIND THE ANTIQUARKS WITH WRONG COLOUR CONNECTIONS
+      DO 11 IHEP=1,NHEP
+      IF(ISTHEP(IHEP).GT.149.AND.ISTHEP(IHEP).LT.155) THEN
+        IF(QBORQQ(IDHW(IHEP))) THEN
+          IF(.NOT.QBORQQ(IDHW(JDAHEP(2,IHEP))).AND.
+     &        JDAHEP(2,IHEP).GT.6) GO TO 11
+        ELSE
+C--Extra check for gamma's
+          IF(IDHW(IHEP).EQ.59) GO TO 11
+          IF(QBORQQ(IDHW(JMOHEP(2,IHEP)))) GO TO 11
+          GO TO 11
+        ENDIF
+        IF(JDAHEP(2,IHEP).LT.6.AND.
+     &    .NOT.QORQQB(IDHW(JDAHEP(2,IHEP)))) GOTO 11
+        NBV=NBV+1
+        IF(NBV.GT.18) CALL HWWARN('HWCBVI',100,*999)
+        IBV(NBV)=IHEP
+        DUNBV(NBV)=.FALSE.
+      ENDIF
+ 11   CONTINUE
+      IF (NBV.EQ.0) RETURN
+      IF(MOD(NBV,3).NE.0) CALL HWWARN('HWCBVI',101,*999)
+C---PROCESS FOUND PARTONS, STARTING AT RANDOM POINT IN LIST
+      NBR=NBV*HWR()
+      DO 100 MBV=1,NBV
+      JBV=MBV+NBR
+      IF (JBV.GT.NBV) JBV=JBV-NBV
+      IF (.NOT.DUNBV(JBV)) THEN
+        DUNBV(JBV)=.TRUE.
+        IP1=IBV(JBV)
+        JP1=HWCBVT(IP1)
+C---FIND ASSOCIATED PARTONS
+        DO 20 KBV=1,NBV
+        IF (.NOT.DUNBV(KBV)) THEN
+          IP2=IBV(KBV)
+          JP2=HWCBVT(IP2)
+          IF (JP2.EQ.JP1) THEN
+            DUNBV(KBV)=.TRUE.
+            DO 15 LBV=1,NBV
+            IF (.NOT.DUNBV(LBV)) THEN
+              IP3=IBV(LBV)
+              JP3=HWCBVT(IP3)
+              IF (JP3.EQ.JP2) THEN
+                DUNBV(LBV)=.TRUE.
+                GO TO 25
+              ENDIF
+            ENDIF
+   15       CONTINUE
+          ENDIF
+        ENDIF
+   20   CONTINUE
+        CALL HWWARN('HWCBVI',102,*999)
+   25   IQ1=0
+C---LOOK FOR DIQUARK
+        IF (ABS(IDHEP(IP1)).GT.100) THEN
+          IQ1=IP1
+          IQ2=IP2
+          IQ3=IP3
+        ELSEIF (ABS(IDHEP(IP2)).GT.100) THEN
+          IQ1=IP2
+          IQ2=IP3
+          IQ3=IP1
+        ELSEIF (ABS(IDHEP(IP3)).GT.100) THEN
+          IQ1=IP3
+          IQ2=IP1
+          IQ3=IP2
+        ENDIF
+        IF (IQ1.EQ.0) THEN
+C---NO DIQUARKS: COMBINE TWO (ANTI)QUARKS
+          IF (ABS(IDHEP(IP1)).GT.3) THEN
+            IQ1=IP2
+            IQ2=IP3
+            IQ3=IP1
+          ELSEIF (ABS(IDHEP(IP2)).GT.3) THEN
+            IQ1=IP3
+            IQ2=IP1
+            IQ3=IP2
+          ELSE
+            IQ1=IP1
+            IQ2=IP2
+            IQ3=IP3
+          ENDIF
+          ID1=IDHEP(IQ1)
+          ID2=IDHEP(IQ2)
+C---CHECK FLAVOURS
+          IF (ID1.GT.0.AND.ID1.LT.4.AND.
+     &        ID2.GT.0.AND.ID2.LT.4) THEN
+            IDQ=IDIQK(ID1,ID2)
+          ELSEIF (ID1.LT.0.AND.ID1.GT.-4.AND.
+     &            ID1.LT.0.AND.ID2.GT.-4) THEN
+            IDQ=IDIQK(-ID1,-ID2)+6
+          ELSE
+C---CANT MAKE DIQUARKS WITH HEAVY QUARKS: TRY CLUSTER SPLITTING
+            CALL HWVSUM(4,PHEP(1,IQ1),PHEP(1,IQ2),PDQ)
+            CALL HWUMAS(PDQ)
+C--Use the original splitting procedure
+            CALL HWCCUT(IQ1,IQ2,PDQ,.FALSE.,SPLIT)
+            IF(SPLIT) GOTO 5
+C--If it fails try the new procedure
+            CALL HWVSUM(4,PDQ,PHEP(1,IQ3),PDQ)
+            CALL HWUMAS(PDQ)
+            IF(ABS(ID1).GT.3) THEN
+              CALL HWCBCT(IQ3,IQ2,IQ1,PDQ,SPLIT)
+            ELSEIF(ABS(ID2).GT.3) THEN
+              CALL HWCBCT(IQ3,IQ1,IQ2,PDQ,SPLIT)
+            ELSE
+              CALL HWWARN('HWCBVI',100,*999)
+            ENDIF
+            IF (SPLIT) GO TO 5
+C---Unable to form cluster; dispose of event
+            CALL HWWARN('HWCBVI',-3,*999)
+          ENDIF
+C---OVERWRITE FIRST AND CANCEL SECOND
+          IDHW(IQ1)=IDQ
+          IDHEP(IQ1)=IDPDG(IDQ)
+          CALL HWVSUM(4,PHEP(1,IQ1),PHEP(1,IQ2),PHEP(1,IQ1))
+          CALL HWUMAS(PHEP(1,IQ1))
+          ISTHEP(IQ2)=0
+C---REMAKE COLOUR CONNECTIONS
+          IF (QORQQB(IDQ)) THEN
+            JMOHEP(2,IQ1)=IQ3
+            JDAHEP(2,IQ3)=IQ1
+          ELSE
+            JDAHEP(2,IQ1)=IQ3
+            JMOHEP(2,IQ3)=IQ1
+          ENDIF
+        ELSE
+C---SPLIT A DIQUARK
+          NHEP=NHEP+1
+          CALL HWVSCA(5,HALF,PHEP(1,IQ1),PHEP(1,IQ1))
+          CALL HWVEQU(5,PHEP(1,IQ1),PHEP(1,NHEP))
+          ISTHEP(NHEP)=150
+          JMOHEP(1,NHEP)=JMOHEP(1,IQ1)
+          JDAHEP(1,NHEP)=0
+C---FIND FLAVOURS
+          IDQ=IDHW(IQ1)
+          DO 30 ID2=1,3
+          DO 30 ID1=1,3
+          IF (IDIQK(ID1,ID2).EQ.IDQ) THEN
+            IDHW(IQ1)=ID1
+            IDHW(NHEP)=ID2
+C---REMAKE COLOUR CONNECTIONS (DIQUARK)
+            JMOHEP(2,IQ1)=IQ2
+            JMOHEP(2,IQ2)=NHEP
+            JMOHEP(2,IQ3)=IQ1
+            JMOHEP(2,NHEP)=IQ3
+            JDAHEP(2,IQ1)=IQ3
+            JDAHEP(2,IQ2)=IQ1
+            JDAHEP(2,IQ3)=NHEP
+            JDAHEP(2,NHEP)=IQ2
+            GO TO 35
+          ELSEIF (IDIQK(ID1,ID2).EQ.IDQ-6) THEN
+            IDHW(IQ1)=ID1+6
+            IDHW(NHEP)=ID2+6
+C---REMAKE COLOUR CONNECTIONS (ANTIDIQUARK)
+            JMOHEP(2,IQ1)=IQ3
+            JMOHEP(2,IQ2)=IQ1
+            JMOHEP(2,IQ3)=NHEP
+            JMOHEP(2,NHEP)=IQ2
+            JDAHEP(2,IQ1)=IQ2
+            JDAHEP(2,IQ2)=NHEP
+            JDAHEP(2,IQ3)=IQ1
+            JDAHEP(2,NHEP)=IQ3
+            GO TO 35
+          ENDIF
+   30     CONTINUE
+          CALL HWWARN('HWCBVI',104,*999)
+   35     IDHEP(IQ1)=IDPDG(IDHW(IQ1))
+          IDHEP(NHEP)=IDPDG(IDHW(NHEP))
+        ENDIF
+      ENDIF
+  100 CONTINUE
+      RETURN
+  999 END
+CDECK  ID>, HWCBVT.
+*CMZ :-
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      FUNCTION HWCBVT(IP)
+C-----------------------------------------------------------------------
+C  Function to find the baryon number violating vertex a parton came from
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER HWCBVT,IP,JP(2),KP,I,J,ID,TYPE,IDM,IDM2,IDM3,IDM4
+      JP(1) = IP
+      ID = IDHW(IP)
+      IF(ID.LE.6.OR.(ID.GE.115.AND.ID.LE.120)) THEN
+        JP(2) = JMOHEP(2,IP)
+      ELSE
+        JP(2) = JDAHEP(2,IP)
+      ENDIF
+      DO I=1,2
+        IDM = JMOHEP(1,JMOHEP(1,JMOHEP(1,JMOHEP(1,JP(I)))))
+        IF(IDHW(IDM).EQ.6.OR.IDHW(IDM).EQ.12) THEN
+          JP(I)=IDM
+        ENDIF
+      ENDDO
+      DO J=1,7
+        DO I=1,2
+          KP = JMOHEP(1,JP(I))
+          IDM = IDHW(KP)
+          IDM2 = IDHW(JDAHEP(1,KP))
+          IDM3 = IDHW(JDAHEP(2,KP))
+          IDM4 = IDHW(JDAHEP(1,KP)+1)
+          IF((ISTHEP(KP).EQ.155.AND.
+     &      ((IDM.GE.449.AND.IDM.LE.457.AND.IDM2.LE.12.AND.
+     &       IDM3.LE.12.AND.IDM4.LE.12).OR.
+     &      (((IDM.GE.411.AND.IDM.LE.424).OR.IDM.EQ.405.OR.IDM.EQ.406)
+     &      .AND.IDM2.LE.12.AND.IDM3.LE.12)))
+     &        .OR.(IDM.EQ.15.AND.IDM2.LE.12.AND.
+     &       IDHW(JMOHEP(1,KP)).LE.12.AND.
+     &       IDHW(JMOHEP(2,KP)).LE.12.AND.IDM3.GE.449.AND.
+     &       IDM3.LE.457).OR.
+     &         (IDM.EQ.15.AND.IDM2.GE.198.AND.IDM2.LE.200.
+     &          AND.ABS(IDPDG(IDM3)).GT.1000000)) THEN
+            IF(IDHW(KP).EQ.449.AND.JDAHEP(1,KP).EQ.JP(I)) THEN
+              KP = JMOHEP(1,KP)
+            ELSEIF(IDHW(KP).EQ.15) THEN
+              TYPE=IDHW(JDAHEP(1,KP))
+              IF(TYPE.GE.7.AND.TYPE.LE.12.AND.
+     &           JMOHEP(2,JDAHEP(2,KP)).EQ.JP(I)) THEN
+                KP=IP
+              ELSEIF(TYPE.LE.6.AND.
+     &           JDAHEP(2,JDAHEP(2,KP)).EQ.JP(I)) THEN
+                KP=IP
+              ELSE
+                HWCBVT = KP
+                RETURN
+              ENDIF
+            ELSE
+              HWCBVT = KP
+              RETURN
+            ENDIF
+          ENDIF
+          JP(I) =KP
+        ENDDO
+      ENDDO
+      HWCBVT = 0
+ 999  END
+CDECK  ID>, HWCCCC.
+*CMZ :-
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCCCC
+C-----------------------------------------------------------------------
+C  Subroutine to correct colour connections after the gluon splitting
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,STFSPT,LHEP,MHEP,RHEP
+      IF(IERROR.NE.0) RETURN
+C--Find the first particle in the event record with status 150
+      DO IHEP=1,NHEP
+        IF(ISTHEP(IHEP).GE.150.AND.ISTHEP(IHEP).LE.154) THEN
+          STFSPT = IHEP
+          GOTO 10
+        ENDIF
+      ENDDO
+ 10   CONTINUE
+C--Now find any that are colour connected to earlier particles
+C--in the event record
+      DO IHEP=STFSPT,NHEP
+C--First the quarks and antidiquarks
+        IF(IDHW(IHEP).LT.6.OR.
+     &     (IDHW(IHEP).GE.115.AND.IDHW(IHEP).LE.120)) THEN
+          IF(JMOHEP(2,IHEP).LT.STFSPT) THEN
+            LHEP = IHEP
+            MHEP = JMOHEP(2,IHEP)
+            RHEP = MHEP
+            IF(MHEP.GT.6) RHEP = JDAHEP(1,MHEP)
+C--As from Rparity connect to particle not to antiparticle
+            IF(IDHW(MHEP).NE.13) THEN
+              JMOHEP(2,LHEP) = RHEP
+            ELSE
+              RHEP = RHEP+1
+              JMOHEP(2,LHEP) = RHEP
+            ENDIF
+          ENDIF
+        ENDIF
+C--Now the antiquarks
+        IF((IDHW(IHEP).GT.6.AND.IDHW(IHEP).LE.12).OR.
+     &     (IDHW(IHEP).GE.109.AND.IDHW(IHEP).LE.114)) THEN
+          IF(JDAHEP(2,IHEP).LT.STFSPT) THEN
+            LHEP = IHEP
+            MHEP = JDAHEP(2,IHEP)
+            RHEP = MHEP
+            IF(MHEP.GT.6) RHEP = JDAHEP(1,MHEP)
+C--As from Rparity connect to antiparticle not particle
+            IF(IDHW(MHEP).NE.13) THEN
+              JDAHEP(2,LHEP) = RHEP
+            ELSE
+              JDAHEP(2,LHEP) = RHEP
+            ENDIF
+          ENDIF
+        ENDIF
+      ENDDO
+      END
+CDECK  ID>, HWCCUT.
+*CMZ :-        -26/04/91  14.29.39  by  Federico Carminati
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCCUT(JHEP,KHEP,PCL,BTCLUS,SPLIT)
+C-----------------------------------------------------------------------
+C     Cuts into 2 the cluster, momentum PCL, made of partons JHEP & KHEP
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWREXQ,HWUPCM,HWR,HWVDOT,EMC,QM1,QM2,EMX,EMY,
+     & QM3,PXY,PCX,PCY,RCM,PCL(5),AX(5),PA(5),PB(5),PC(5),SKAPPA,DELTM,
+     & VSCA,VTMP(4),RKAPPA,VCLUS
+      INTEGER HWRINT,JHEP,KHEP,LHEP,MHEP,ID1,ID2,ID3,NTRY,NTRYMX,J,IB
+      LOGICAL BTCLUS,SPLIT
+      EXTERNAL HWREXQ,HWUPCM,HWR,HWVDOT,HWRINT
+      COMMON/HWCFRM/VCLUS(4,NMXHEP)
+      PARAMETER (SKAPPA=1.,NTRYMX=100)
+      IF (IERROR.NE.0) RETURN
+      EMC=PCL(5)
+      ID1=IDHW(JHEP)
+      ID2=IDHW(KHEP)
+      QM1=RMASS(ID1)
+      QM2=RMASS(ID2)
+      SPLIT=.FALSE.
+      NTRY=0
+C Decide if cluster contains a b-(anti)quark
+      IF (ID1.EQ.5.OR.ID1.EQ.11.OR.ID2.EQ.5.OR.ID2.EQ.11) THEN
+        IB=2
+      ELSE
+        IB=1
+      ENDIF
+      IF (BTCLUS) THEN
+C Split beam and target clusters as soft clusters
+C Both (remnant) children treated like soft clusters if IOPREM=0(1)
+  10    ID3=HWRINT(1,2)
+        QM3=RMASS(ID3)
+        IF (EMC.LE.QM1+QM2+2.*QM3) THEN
+          ID3=3-ID3
+          QM3=RMASS(ID3)
+          IF (EMC.LE.QM1+QM2+2.*QM3) RETURN
+        ENDIF
+        PXY=EMC-QM1-QM2-TWO*QM3
+        IF (ISTHEP(JHEP).EQ.153.OR.ISTHEP(JHEP).EQ.154.OR.
+     &      IOPREM.EQ.0) THEN
+          EMX=QM1+QM3+HWREXQ(BTCLM,PXY)
+        ELSE
+          EMX=QM1+QM3+PXY*HWR()**PSPLT(IB)
+        ENDIF
+        IF (ISTHEP(KHEP).EQ.153.OR.ISTHEP(KHEP).EQ.154.OR.
+     &      IOPREM.EQ.0) THEN
+          EMY=QM2+QM3+HWREXQ(BTCLM,PXY)
+        ELSE
+          EMY=QM2+QM3+PXY*HWR()**PSPLT(IB)
+        ENDIF
+        IF (EMX+EMY.GE.EMC) THEN
+          NTRY=NTRY+1
+          IF (NTRY.GT.NTRYMX) RETURN
+          GOTO 10
+        ENDIF
+        PCX=HWUPCM(EMX,QM1,QM3)
+        PCY=HWUPCM(EMY,QM2,QM3)
+      ELSE
+C Choose fragment masses for ordinary cluster
+        PXY=EMC-QM1-QM2
+  20    NTRY=NTRY+1
+        IF (NTRY.GT.NTRYMX) RETURN
+  30    EMX=QM1+PXY*HWR()**PSPLT(IB)
+        EMY=QM2+PXY*HWR()**PSPLT(IB)
+        IF (EMX+EMY.GE.EMC) GOTO 30
+C u,d,s pair production with weights QWT
+  40    ID3=HWRINT(1,3)
+        IF (QWT(ID3).LT.HWR()) GOTO 40
+        QM3=RMASS(ID3)
+        PCX=HWUPCM(EMX,QM1,QM3)
+        IF (PCX.LT.ZERO) GOTO 20
+        PCY=HWUPCM(EMY,QM2,QM3)
+        IF (PCY.LT.ZERO) GOTO 20
+        SPLIT=.TRUE.
+      ENDIF
+C Boost antiquark to CoM frame to find axis
+      CALL HWULOF(PCL,PHEP(1,KHEP),AX)
+      RCM=1./SQRT(HWVDOT(3,AX,AX))
+      CALL HWVSCA(3,RCM,AX,AX)
+C Construct new CoM momenta (collinear)
+      PXY=HWUPCM(EMC,EMX,EMY)
+      CALL HWVSCA(3,PXY,AX,PC)
+      PC(4)=SQRT(PXY**2+EMY**2)
+      PC(5)=EMY
+      CALL HWVSCA(3,PCY,AX,PA)
+      PA(4)=SQRT(PCY**2+QM2**2)
+      PA(5)=QM2
+      CALL HWULOB(PC,PA,PB)
+      CALL HWVDIF(4,PC,PB,PA)
+      PA(5)=QM3
+      LHEP=NHEP+1
+      MHEP=NHEP+2
+      CALL HWULOB(PCL,PB,PHEP(1,KHEP))
+      CALL HWULOB(PCL,PA,PHEP(1,MHEP))
+      CALL HWVSCA(3,-ONE,PC,PC)
+      PC(4)=EMC-PC(4)
+      PC(5)=EMX
+      CALL HWVSCA(3,PCX,AX,PA)
+      PA(4)=SQRT(PCX**2+QM3**2)
+      CALL HWULOB(PC,PA,PB)
+      CALL HWULOB(PCL,PB,PHEP(1,LHEP))
+      DO 50 J=1,4
+  50  PHEP(J,JHEP)=PCL(J)-PHEP(J,KHEP)-PHEP(J,LHEP)-PHEP(J,MHEP)
+      PHEP(5,JHEP)=QM1
+      CALL HWVEQU(4,VHEP(1,LHEP),VHEP(1,MHEP))
+C Construct new vertex positions
+      RKAPPA=GEV2MM/SKAPPA
+      CALL HWVSCA(3,RKAPPA,AX,AX)
+      DELTM=(EMX-EMY)*(EMX+EMY)/(TWO*EMC)
+      CALL HWVSCA(3,DELTM,AX,VTMP)
+      VTMP(4)=(HALF*EMC-PXY)*RKAPPA
+      CALL HWULB4(PCL,VTMP,VTMP)
+      CALL HWVSUM(4,VTMP,VCLUS(1,JHEP),VHEP(1,LHEP))
+      CALL HWVEQU(4,VHEP(1,LHEP),VHEP(1,MHEP))
+      VSCA=0.25*EMC+HALF*(PXY+DELTM)
+      CALL HWVSCA(3,VSCA,AX,VTMP)
+      VTMP(4)=(EMC-VSCA)*RKAPPA
+      CALL HWULB4(PCL,VTMP,VTMP)
+      CALL HWVSUM(4,VTMP,VCLUS(1,JHEP),VCLUS(1,MHEP))
+      VSCA=-0.25*EMC+HALF*(DELTM-PXY)
+      CALL HWVSCA(3,VSCA,AX,VTMP)
+      VTMP(4)=(EMC+VSCA)*RKAPPA
+      CALL HWULB4(PCL,VTMP,VTMP)
+      CALL HWVSUM(4,VTMP,VCLUS(1,JHEP),VCLUS(1,JHEP))
+C (Re-)label quarks
+      IDHW(LHEP)=ID3+6
+      IDHW(MHEP)=ID3
+      IDHEP(MHEP)= IDPDG(ID3)
+      IDHEP(LHEP)=-IDPDG(ID3)
+      ISTHEP(LHEP)=151
+      ISTHEP(MHEP)=151
+      JMOHEP(2,JHEP)=LHEP
+      JDAHEP(2,KHEP)=MHEP
+      JMOHEP(1,LHEP)=JMOHEP(1,KHEP)
+      JMOHEP(2,LHEP)=MHEP
+      JDAHEP(1,LHEP)=0
+      JDAHEP(2,LHEP)=JHEP
+      JMOHEP(1,MHEP)=JMOHEP(1,JHEP)
+      JMOHEP(2,MHEP)=KHEP
+      JDAHEP(1,MHEP)=0
+      JDAHEP(2,MHEP)=LHEP
+      NHEP=NHEP+2
+  999 END
+CDECK  ID>, HWCDEC.
+*CMZ :-        -26/04/91  10.18.56  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCDEC
+C-----------------------------------------------------------------------
+C     DECAYS CLUSTERS INTO PRIMARY HADRONS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER JCL,KCL,IP,JP,KP,IST,ID1,ID2,ID3
+      IF (IERROR.NE.0) RETURN
+      IF (IPROC/1000.EQ.9.OR.IPROC/1000.EQ.5) THEN
+C---RELABEL CLUSTER CONNECTED TO REMNANT IN DIS
+        DO 10 JCL=2,NHEP
+        IF (ISTHEP(JCL).EQ.164) GOTO 20
+        IF (ISTHEP(JCL).EQ.165) THEN
+          IP=JMOHEP(1,JCL)
+          JP=JMOHEP(2,JCL)
+          KP=IP
+          IF (ISTHEP(IP).EQ.162) THEN
+            KP=JP
+            JP=IP
+          ENDIF
+          IF (JMOHEP(2,KP).NE.JP) THEN
+            IP=JMOHEP(2,KP)
+          ELSE
+            IP=JDAHEP(2,KP)
+          ENDIF
+          KCL=JDAHEP(1,IP)
+          IF (ISTHEP(KCL)/10.NE.16) CALL HWWARN('HWCDEC',100,*999)
+          ISTHEP(KCL)=164
+          GOTO 20
+        ENDIF
+   10   CONTINUE
+      ENDIF
+   20 CONTINUE
+      DO 30 JCL=1,NHEP
+      IST=ISTHEP(JCL)
+      IF (IST.GT.162.AND.IST.LT.166) THEN
+C---DON'T HADRONIZE BEAM/TARGET CLUSTERS
+        IF (IST.EQ.163.OR..NOT.GENSOF) THEN
+C---SET UP FLAVOURS FOR CLUSTER DECAY
+          CALL HWCFLA(IDHW(JMOHEP(1,JCL)),IDHW(JMOHEP(2,JCL)),ID1,ID3)
+          CALL HWCHAD(JCL,ID1,ID3,ID2)
+        ENDIF
+      ENDIF
+   30 CONTINUE
+      ISTAT=50
+  999 END
+CDECK  ID>, HWCFLA.
+*CMZ :-        -26/04/91  10.18.56  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCFLA(JD1,JD2,ID1,ID2)
+C-----------------------------------------------------------------------
+C     SETS UP FLAVOURS FOR CLUSTER DECAY
+C-----------------------------------------------------------------------
+      INTEGER JD1,JD2,ID1,ID2,JD,JDEC(12)
+      DATA JDEC/1,2,3,10,11,12,4,5,6,7,8,9/
+      JD=JD1
+      IF (JD.GT.12) JD=JD-108
+      ID1=JDEC(JD)
+      JD=JD2
+      IF (JD.GT.12) JD=JD-96
+      ID2=JDEC(JD-6)
+      END
+CDECK  ID>, HWCFOR.
+*CMZ :-        -26/04/91  14.15.56  by  Federico Carminati
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCFOR
+C-----------------------------------------------------------------------
+C     Converts colour-connected quark-antiquark pairs into clusters
+C     Modified by IGK to include BRW's colour rearrangement and
+C     MHS's cluster vertices
+C     MODIFIED 16/10/97 BY BRW FOR SUSY PROCESSES
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWULDO,HWVDOT,HWR,HWUPCM,DCL0,DCL(4),DCL1,
+     & DFAC,DISP1(4),DISP2(4),DMAX,PCL(5),DOT1,DOT2,FAC,VCLUS,SCA1,SCA2,
+     & EM0,EM1,EM2,PC0,PC1
+      INTEGER HWRINT,MAP(120),IBHEP,IBCL,JBHEP,JHEP,
+     & KHEP,LHEP,LCL,IHEP,MCL,I,ISTJ,ISTK,JCL,ID1,ID3,L
+      LOGICAL HWRLOG,SPLIT
+      EXTERNAL HWULDO,HWVDOT,HWR,HWUPCM,HWRINT
+      COMMON/HWCFRM/VCLUS(4,NMXHEP)
+      DATA MAP/1,2,3,4,5,6,1,2,3,4,5,6,96*0,7,8,9,10,11,12,7,8,9,10,11,
+     & 12/
+      IF (IERROR.NE.0) RETURN
+C Split gluons
+      CALL HWCGSP
+C Find colour partners after baryon number violating event
+      IF (HVFCEN) THEN
+        IF(RPARTY) THEN
+          CALL HVCBVI
+        ELSE
+          CALL HWCBVI
+        ENDIF
+      ENDIF
+      IF (IERROR.NE.0) RETURN
+C Look for partons to cluster
+      DO 10 IBHEP=1,NHEP
+  10  IF (ISTHEP(IBHEP).GE.150.AND.ISTHEP(IBHEP).LE.154) GOTO 20
+      IBCL=1
+      GOTO 130
+  20  CONTINUE
+C--Final check for colour disconnections
+      DO 25 JHEP=IBHEP,NHEP
+        IF (ISTHEP(JHEP).GE.150.AND.ISTHEP(JHEP).LE.154.AND.
+     &      QORQQB(IDHW(JHEP))) THEN
+          KHEP=JMOHEP(2,JHEP)
+C BRW FIX 13/03/99
+          IF (KHEP.EQ.0.OR..NOT.(
+     &      ISTHEP(KHEP).GE.150.AND.ISTHEP(KHEP).LE.154.AND.
+     &      QBORQQ(IDHW(KHEP)))) THEN
+            DO KHEP=IBHEP,NHEP
+              IF (ISTHEP(KHEP).GE.150.AND.ISTHEP(KHEP).LE.154
+     &        .AND.QBORQQ(IDHW(KHEP))) THEN
+                LHEP=JDAHEP(2,KHEP)
+                IF (LHEP.EQ.0.OR..NOT.(
+     &          ISTHEP(LHEP).GE.150.AND.ISTHEP(LHEP).LE.154.AND.
+     &          QORQQB(IDHW(LHEP)))) THEN
+                  JMOHEP(2,JHEP)=KHEP
+                  JDAHEP(2,KHEP)=JHEP
+                  GOTO 25
+                ENDIF
+              ENDIF
+            ENDDO
+C END FIX
+            CALL HWWARN('HWCFOR',100,*999)
+          ENDIF
+        ENDIF
+  25  CONTINUE
+      IF (CLRECO) THEN
+C Allow for colour rearrangement of primary clusters
+        NRECO=0
+C Randomize starting point
+        JBHEP=HWRINT(IBHEP,NHEP)
+        JHEP=JBHEP
+  30    JHEP=JHEP+1
+        IF (JHEP.GT.NHEP) JHEP=IBHEP
+        IF (ISTHEP(JHEP).GE.150.AND.ISTHEP(JHEP).LE.154.AND.
+     &      QORQQB(IDHW(JHEP))) THEN
+C Find colour connected antiquark or diquark
+          KHEP=JMOHEP(2,JHEP)
+C Find partner antiquark or diquark
+          LHEP=JDAHEP(2,JHEP)
+C Find closest antiquark or diquark
+          DCL0=1.D15
+          LCL=0
+          DO 40 IHEP=IBHEP,NHEP
+          IF (ISTHEP(IHEP).GE.150.AND.ISTHEP(IHEP).LE.154.AND.
+     &        QBORQQ(IDHW(IHEP))) THEN
+C Check whether already reconnected
+            IF (JDAHEP(2,IHEP).GT.0.AND.IHEP.NE.LHEP) THEN
+              CALL HWVDIF(4,VHEP(1,IHEP),VHEP(1,JHEP),DCL)
+              DCL1=ABS(HWULDO(DCL,DCL))
+              IF (DCL1.LT.DCL0) THEN
+                DCL0=DCL1
+                LCL=IHEP
+              ENDIF
+            ENDIF
+          ENDIF
+  40      CONTINUE
+          IF (LCL.NE.0.AND.LCL.NE.KHEP) THEN
+            MCL=JDAHEP(2,LCL)
+            IF (JDAHEP(2,MCL).NE.KHEP) THEN
+C Pairwise reconnection is possible
+              CALL HWVDIF(4,VHEP(1,KHEP),VHEP(1,MCL ),DCL)
+              DCL0=DCL0+ABS(HWULDO(DCL,DCL))
+              CALL HWVDIF(4,VHEP(1,JHEP),VHEP(1,KHEP),DCL)
+              DCL1=ABS(HWULDO(DCL,DCL))
+              CALL HWVDIF(4,VHEP(1,LCL ),VHEP(1,MCL ),DCL)
+              DCL1=DCL1+ABS(HWULDO(DCL,DCL))
+              IF (DCL0.LT.DCL1.AND.HWRLOG(PRECO)) THEN
+C Reconnection occurs
+                JMOHEP(2,JHEP)= LCL
+                JDAHEP(2,LCL )=-JHEP
+                JMOHEP(2,MCL) = KHEP
+                JDAHEP(2,KHEP)=-MCL
+                NRECO=NRECO+1
+              ENDIF
+            ENDIF
+          ENDIF
+        ENDIF
+        IF (JHEP.NE.JBHEP) GOTO 30
+        IF (NRECO.NE.0) THEN
+          DO 50 IHEP=IBHEP,NHEP
+  50      JDAHEP(2,IHEP)=ABS(JDAHEP(2,IHEP))
+        ENDIF
+      ENDIF
+C Find (adjusted) cluster positions using MHS prescription
+      DFAC=10
+      DMAX=1D-10
+      DO 70 JHEP=IBHEP,NHEP
+      IF (ISTHEP(JHEP).GE.150.AND.ISTHEP(JHEP).LE.154.AND.
+     &    QORQQB(IDHW(JHEP))) THEN
+        KHEP=JMOHEP(2,JHEP)
+        CALL HWUDKL(IDHW(JHEP),PHEP(1,JHEP),DISP1)
+        CALL HWVSCA(4,DFAC,DISP1,DISP1)
+        CALL HWUDKL(IDHW(KHEP),PHEP(1,KHEP),DISP2)
+        CALL HWVSCA(4,DFAC,DISP2,DISP2)
+C Rescale the lengths of DISP1,DISP2 if too long
+        DOT1=HWVDOT(3,DISP1,DISP1)
+        DOT2=HWVDOT(3,DISP2,DISP2)
+        IF (MAX(DOT1,DOT2).GT.DMAX**2) THEN
+          CALL HWVSCA(4,DMAX/SQRT(DOT1),DISP1,DISP1)
+          CALL HWVSCA(4,DMAX/SQRT(DOT2),DISP2,DISP2)
+        ENDIF
+        CALL HWVSUM(4,PHEP(1,JHEP),PHEP(1,KHEP),PCL)
+        DOT1=HWVDOT(3,DISP1,PCL)
+        DOT2=HWVDOT(3,DISP2,PCL)
+C If PCL > 90^o from either quark, use a vector which isn't
+        IF (DOT1.LE.ZERO.OR. DOT2.LE.ZERO) THEN
+          CALL HWVSUM(4,DISP1,DISP2,PCL)
+          DOT1=HWVDOT(3,DISP1,PCL)
+          DOT2=HWVDOT(3,DISP2,PCL)
+        ENDIF
+C If vectors are exactly opposite each other this method cannot work
+        IF (DOT1.EQ.ZERO.OR.DOT2.EQ.ZERO) THEN
+C So use midpoint of quark constituents
+          CALL HWVSUM(4,VHEP(1,JHEP),VHEP(1,KHEP),VCLUS(1,JHEP))
+          CALL HWVSCA(4,HALF,VCLUS(1,JHEP),VCLUS(1,JHEP))
+          GOTO 70
+        ENDIF
+C Rescale DISP1 or DISP2 to give equal components in the PCL direction
+        FAC=DOT1/DOT2
+        IF (FAC.GT.ONE) THEN
+          CALL HWVSCA(4,    FAC,DISP2,DISP2)
+          DOT2=DOT1
+        ELSE
+          CALL HWVSCA(4,ONE/FAC,DISP1,DISP1)
+          DOT1=DOT2
+        ENDIF
+C Shift VHEP(1,JHEP) or VHEP(1,KHEP) s.t. their line is perp to PCL
+        FAC=(HWVDOT(3,PCL,VHEP(1,KHEP))
+     &      -HWVDOT(3,PCL,VHEP(1,JHEP)))/DOT1
+        SCA1=MAX(ONE,ONE+FAC)
+        SCA2=MAX(ONE,ONE-FAC)
+        DO 60 I=1,4
+  60    VCLUS(I,JHEP)=.5*(VHEP(I,JHEP)+VHEP(I,KHEP)
+     &                   +SCA1*DISP1(I)+SCA2*DISP2(I))
+      ENDIF
+  70  CONTINUE
+C First chop up beam/target clusters
+      DO 80 JHEP=IBHEP,NHEP
+      KHEP=JMOHEP(2,JHEP)
+      ISTJ=ISTHEP(JHEP)
+      ISTK=ISTHEP(KHEP)
+C--PR MOD here 8/7/99
+      IF (QORQQB(IDHW(JHEP)).AND.
+     &   (((ISTJ.EQ.153.OR.ISTJ.EQ.154).AND.ISTK.NE.151.AND.ISTK.NE.0)
+     &   .OR.((ISTK.EQ.153.OR.ISTK.EQ.154).
+     &   AND.ISTJ.NE.151.AND.ISTJ.NE.0))) THEN
+C--end
+        CALL HWVSUM(4,PHEP(1,JHEP),PHEP(1,KHEP),PCL)
+        CALL HWUMAS(PCL)
+        CALL HWCCUT(JHEP,KHEP,PCL,.TRUE.,SPLIT)
+      ENDIF
+  80  CONTINUE
+C Second chop up massive pairs
+      DO 100 JHEP=IBHEP,NMXHEP
+      IF (JHEP.GT.NHEP) GOTO 110
+      IF (ISTHEP(JHEP).GE.150.AND.ISTHEP(JHEP).LE.154.AND.
+     &    QORQQB(IDHW(JHEP))) THEN
+  90    KHEP=JMOHEP(2,JHEP)
+        CALL HWVSUM(4,PHEP(1,JHEP),PHEP(1,KHEP),PCL)
+        CALL HWUMAS(PCL)
+        IF (PCL(5).GT.CTHRPW(MAP(IDHW(JHEP)),MAP(IDHW(KHEP)))) THEN
+          CALL HWCCUT(JHEP,KHEP,PCL,.FALSE.,SPLIT)
+          IF (SPLIT) GOTO 90
+        ENDIF
+      ENDIF
+  100 CONTINUE
+C Third create clusters and store production vertex
+  110 IBCL=NHEP+1
+      JCL=NHEP
+      DO 120 JHEP=IBHEP,NHEP
+      IF (ISTHEP(JHEP).GE.150.AND.ISTHEP(JHEP).LE.154.AND.
+     &    QORQQB(IDHW(JHEP))) THEN
+        JCL=JCL+1
+        IF(JCL.GT.NMXHEP) CALL HWWARN('HWCFOR',105,*999)
+        IDHW(JCL)=19
+        IDHEP(JCL)=91
+        KHEP=JMOHEP(2,JHEP)
+        IF (KHEP.EQ.0.OR..NOT.(
+     &    ISTHEP(KHEP).GE.150.AND.ISTHEP(KHEP).LE.154.AND.
+     &    QBORQQ(IDHW(KHEP)))) CALL HWWARN('HWCFOR',104,*999)
+        CALL HWVSUM(4,PHEP(1,JHEP),PHEP(1,KHEP),PHEP(1,JCL))
+        CALL HWUMAS(PHEP(1,JCL))
+        IF (ISTHEP(JHEP).EQ.153.OR.ISTHEP(KHEP).EQ.153) THEN
+          ISTHEP(JCL)=164
+        ELSEIF (ISTHEP(JHEP).EQ.154.OR.ISTHEP(KHEP).EQ.154) THEN
+          ISTHEP(JCL)=165
+        ELSE
+          ISTHEP(JCL)=163
+        ENDIF
+        JMOHEP(1,JCL)=JHEP
+        JMOHEP(2,JCL)=KHEP
+        JDAHEP(1,JCL)=0
+        JDAHEP(2,JCL)=0
+        JDAHEP(1,JHEP)=JCL
+        JDAHEP(1,KHEP)=JCL
+        ISTHEP(JHEP)=ISTHEP(JHEP)+8
+        ISTHEP(KHEP)=ISTHEP(KHEP)+8
+        CALL HWVEQU(4,VCLUS(1,JHEP),VHEP(1,JCL))
+      ENDIF
+  120 CONTINUE
+      NHEP=JCL
+C Fix up momenta for single-hadron clusters
+  130 DO 150 JCL=IBCL,NHEP
+C Don't hadronize beam/target clusters
+      IF (ISTHEP(JCL).LT.163.OR.ISTHEP(JCL).GT.165) GOTO 150
+      IF (ISTHEP(JCL).NE.163.AND.GENSOF) GOTO 150
+C Set up flavours for cluster decay
+      CALL HWCFLA(IDHW(JMOHEP(1,JCL)),IDHW(JMOHEP(2,JCL)),ID1,ID3)
+      EM0=PHEP(5,JCL)
+      IF ((B1LIM.EQ.ZERO).OR.(ID1.NE.11.AND.ID3.NE.11)) THEN
+        IF (EM0.GT.RMIN(ID1,2)+RMIN(2,ID3)) GOTO 150
+      ELSE
+C Special for b clusters: allow 1-hadron decay above threshold
+        IF (B1LIM*HWR().LT.EM0/(RMIN(ID1,2)+RMIN(2,ID3))-1.)
+     &   GOTO 150
+      ENDIF
+      EM1=RMIN(ID1,ID3)
+      IF (ABS(EM0-EM1).LT.1.D-5) GOTO 150
+C Decide to go backward or forward to transfer 4-momentum
+      L=1-TWO*INT(HALF+HWR())
+      MCL=NHEP-IBCL+1
+      LCL=JCL
+      DO 140 I=1,MCL
+      LCL=LCL+L
+      IF (LCL.LT.IBCL) LCL=LCL+MCL
+      IF (LCL.GT.NHEP) LCL=LCL-MCL
+      IF (LCL.EQ.JCL) THEN
+        IF (EM0.GE.EM1+RMIN(1,1)) GOTO 150
+        CALL HWWARN('HWCFOR',101,*999)
+      ENDIF
+      IF (ISTHEP(LCL).LT.163.OR.ISTHEP(LCL).GT.165) GOTO 140
+C Rescale momenta in 2-cluster CoM
+      CALL HWVSUM(4,PHEP(1,JCL),PHEP(1,LCL),PCL)
+      CALL HWUMAS(PCL)
+      EM2=PHEP(5,LCL)
+      PC0=HWUPCM(PCL(5),EM0,EM2)
+      PC1=HWUPCM(PCL(5),EM1,EM2)
+      IF (PC1.LT.ZERO) THEN
+C Need to rescale other mass as well
+        CALL HWCFLA(IDHW(JMOHEP(1,LCL)),IDHW(JMOHEP(2,LCL)),ID1,ID3)
+        EM2=RMIN(ID1,ID3)
+        PC1=HWUPCM(PCL(5),EM1,EM2)
+        IF (PC1.LT.ZERO) GOTO 140
+        PHEP(5,LCL)=EM2
+      ENDIF
+      IF (PC0.GT.ZERO) THEN
+        PC0=PC1/PC0
+        CALL HWULOF(PCL,PHEP(1,JCL),PHEP(1,JCL))
+        CALL HWVSCA(3,PC0,PHEP(1,JCL),PHEP(1,JCL))
+        PHEP(4,JCL)=SQRT(PC1**2+EM1**2)
+        PHEP(5,JCL)=EM1
+        CALL HWULOB(PCL,PHEP(1,JCL),PHEP(1,JCL))
+        CALL HWVDIF(4,PCL,PHEP(1,JCL),PHEP(1,LCL))
+        GOTO 150
+      ELSEIF (PC0.EQ.ZERO) THEN
+        PHEP(5,JCL)=EM1
+        CALL HWDTWO(PCL,PHEP(1,JCL),PHEP(1,LCL),PC1,TWO,.TRUE.)
+        GOTO 150
+      ELSE
+        CALL HWWARN('HWCFOR',102,*999)
+      ENDIF
+  140 CONTINUE
+      CALL HWWARN('HWCFOR',103,*999)
+  150 CONTINUE
+      ISTAT=60
+C Non-partons labelled as partons (ie photons) should get copied
+      DO 160 IHEP=1,NHEP
+      IF (ISTHEP(IHEP).EQ.150) THEN
+        NHEP=NHEP+1
+        JDAHEP(1,IHEP)=NHEP
+        ISTHEP(IHEP)=157
+        ISTHEP(NHEP)=190
+        IDHW(NHEP)=IDHW(IHEP)
+        IDHEP(NHEP)=IDPDG(IDHW(IHEP))
+        CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,NHEP))
+        CALL HWVEQU(4,VHEP(1,IHEP),VHEP(1,NHEP))
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=JMOHEP(1,IHEP)
+        JDAHEP(1,NHEP)=0
+        JDAHEP(2,NHEP)=0
+      ENDIF
+  160 CONTINUE
+  999 END
+CDECK  ID>, HWCGSP.
+*CMZ :-        -13/07/92  20.15.54  by  Mike Seymour
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCGSP
+C-----------------------------------------------------------------------
+C     SPLITS ANY TIMELIKE GLUONS REMAINING AFTER PERTURBATIVE
+C     BRANCHING INTO LIGHT (I.E. U OR D) Q-QBAR PAIRS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,PF
+      INTEGER HWRINT,IHEP,JHEP,KHEP,LHEP,MHEP,ID,J,IST
+      EXTERNAL HWR,HWRINT
+      IF (NGSPL.EQ.0) CALL HWWARN('HWCGSP',400,*999)
+      LHEP=NHEP-1
+      MHEP=NHEP
+      DO 100 IHEP=1,NHEP
+      IF (ISTHEP(IHEP).GE.147.AND.ISTHEP(IHEP).LE.149) THEN
+        JHEP=JMOHEP(2,IHEP)
+C BRW FIX 12/03/99
+        IF (JHEP.LE.0) THEN
+          KHEP=0
+          DO JHEP=1,NHEP
+            IF (ISTHEP(JHEP).GE.147.AND.ISTHEP(JHEP).LE.149
+     &      .AND.JDAHEP(2,JHEP).LE.0) THEN
+              KHEP=KHEP+1
+              JMOHEP(2,IHEP)=JHEP
+              JDAHEP(2,JHEP)=IHEP
+            ENDIF
+          ENDDO
+          IF (KHEP.EQ.0) CALL HWWARN('HWCGSP',102,*999)
+          IF (KHEP.NE.1) CALL HWWARN('HWCGSP',103,*999)
+        ENDIF
+C END FIX
+C---CHECK FOR DECAYED HEAVY ANTIQUARKS
+        IF (ISTHEP(JHEP).EQ.155) THEN
+          JHEP=JDAHEP(1,JDAHEP(2,JHEP))
+          DO 10 J=JDAHEP(1,JHEP),JDAHEP(2,JHEP)
+  10      IF (ISTHEP(J).EQ.149.AND.JDAHEP(2,J).EQ.0) GOTO 20
+          CALL HWWARN('HWCGSP',100,*999)
+  20      JHEP=J
+        ENDIF
+        KHEP=JDAHEP(2,IHEP)
+C BRW FIX 12/03/99
+        IF (KHEP.LE.0) THEN
+          KHEP=0
+          DO JHEP=1,NHEP
+            IF (ISTHEP(JHEP).GE.147.AND.ISTHEP(JHEP).LE.149
+     &      .AND.JMOHEP(2,JHEP).LE.0) THEN
+              KHEP=KHEP+1
+              JDAHEP(2,IHEP)=JHEP
+              JMOHEP(2,JHEP)=IHEP
+            ENDIF
+          ENDDO
+          IF (KHEP.EQ.0) CALL HWWARN('HWCGSP',104,*999)
+          IF (KHEP.NE.1) CALL HWWARN('HWCGSP',105,*999)
+          KHEP=JDAHEP(2,IHEP)
+        ENDIF
+C END FIX
+C---CHECK FOR DECAYED HEAVY QUARKS
+        IF (ISTHEP(KHEP).EQ.155)  CALL HWWARN('HWCGSP',101,*999)
+        IF (IDHW(IHEP).EQ.13) THEN
+C---SPLIT A GLUON
+          LHEP=LHEP+2
+          MHEP=MHEP+2
+          IF(MHEP.GT.NMXHEP) CALL HWWARN('HWCGSP',106,*999)
+  30      ID=HWRINT(1,NGSPL)
+          IF (PGSPL(ID).LT.PGSMX*HWR()) GOTO 30
+          PHEP(5,LHEP)=RMASS(ID)
+          PHEP(5,MHEP)=RMASS(ID)
+C---ASSUME ISOTROPIC ANGULAR DISTRIBUTION
+          IF (PHEP(5,IHEP).GT.PHEP(5,LHEP)+PHEP(5,MHEP)) THEN
+            CALL HWDTWO(PHEP(1,IHEP),PHEP(1,LHEP),
+     &                  PHEP(1,MHEP),PGSPL(ID),TWO,.TRUE.)
+          ELSE
+            PF=HWR()
+            CALL HWVSCA(4,PF,PHEP(1,IHEP),PHEP(1,LHEP))
+            CALL HWVDIF(4,PHEP(1,IHEP),PHEP(1,LHEP),PHEP(1,MHEP))
+            PHEP(5,LHEP)=PF*PHEP(5,IHEP)
+            PHEP(5,MHEP)=PHEP(5,IHEP)-PHEP(5,LHEP)
+          ENDIF
+          CALL HWUDKL(13,PHEP(1,IHEP),VHEP(1,LHEP))
+          CALL HWVSUM(4,VHEP(1,IHEP),VHEP(1,LHEP),VHEP(1,LHEP))
+          CALL HWVEQU(4,VHEP(1,LHEP),VHEP(1,MHEP))
+          IDHW(LHEP)=ID+6
+          IDHW(MHEP)=ID
+          IDHEP(MHEP)= IDPDG(ID)
+          IDHEP(LHEP)=-IDPDG(ID)
+          ISTHEP(IHEP)=2
+          ISTHEP(LHEP)=150
+          ISTHEP(MHEP)=150
+C---NEW COLOUR CONNECTIONS
+          IF(RPARTY.OR.JMOHEP(2,KHEP).EQ.IHEP) JMOHEP(2,KHEP)=LHEP
+          IF(RPARTY.OR.JDAHEP(2,JHEP).EQ.IHEP) JDAHEP(2,JHEP)=MHEP
+          JMOHEP(1,LHEP)=JMOHEP(1,IHEP)
+          JMOHEP(2,LHEP)=MHEP
+          JMOHEP(1,MHEP)=JMOHEP(1,IHEP)
+          JMOHEP(2,MHEP)=JHEP
+          JDAHEP(1,LHEP)=0
+          JDAHEP(2,LHEP)=KHEP
+          JDAHEP(1,MHEP)=0
+          JDAHEP(2,MHEP)=LHEP
+          JDAHEP(1,IHEP)=LHEP
+          JDAHEP(2,IHEP)=MHEP
+        ELSE
+C---COPY A NON-GLUON
+          LHEP=LHEP+1
+          MHEP=MHEP+1
+          IF(MHEP.GT.NMXHEP) CALL HWWARN('HWCGSP',107,*999)
+          CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,MHEP))
+          CALL HWVEQU(4,VHEP(1,IHEP),VHEP(1,MHEP))
+          IDHW(MHEP)=IDHW(IHEP)
+          IDHEP(MHEP)=IDHEP(IHEP)
+          IST=ISTHEP(IHEP)
+          ISTHEP(IHEP)=2
+          IF (IST.EQ.149) THEN
+            ISTHEP(MHEP)=150
+          ELSE
+            ISTHEP(MHEP)=IST+6
+          ENDIF
+C---NEW COLOUR CONNECTIONS
+          IF(RPARTY.OR.JMOHEP(2,KHEP).EQ.IHEP)
+     &      JMOHEP(2,KHEP)=MHEP
+          IF(RPARTY.OR.(JHEP.NE.IHEP.AND.JDAHEP(2,JHEP).EQ.IHEP))
+     &      JDAHEP(2,JHEP)=MHEP
+          JMOHEP(1,MHEP)=JMOHEP(1,IHEP)
+          JMOHEP(2,MHEP)=JMOHEP(2,IHEP)
+          JDAHEP(1,MHEP)=0
+          JDAHEP(2,MHEP)=JDAHEP(2,IHEP)
+          JDAHEP(1,IHEP)=MHEP
+        ENDIF
+      ENDIF
+  100 CONTINUE
+      NHEP=MHEP
+  999 END
+CDECK  ID>, HWCHAD.
+*CMZ :-        -26/04/91  14.00.57  by  Federico Carminati
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWCHAD(JCL,ID1,ID3,ID2)
+C-----------------------------------------------------------------------
+C     HADRONIZES CLUSTER JCL, CONSISTING OF PARTONS ID1,ID3
+C     ID2 RETURNS PARTON-ANTIPARTON PAIR CREATED
+C     (IN SPECIAL CLUSTER CODE - SEE HWCFLA)
+C
+C MODIFIED 15/11/99 TO SMEAR POSITIONS OF HADRONS BY 1/(CLUSTER MASS)
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,HWRGAU,HWVDOT,EM0,EM1,EM2,EMADU,EMSQ,
+     & PCMAX,PCM,PTEST,PCQK,PP(5),EMLOW,RMAT(3,3),CT,ST,CX,SX,HPSMR
+      INTEGER HWRINT,JCL,ID1,ID2,ID3,ID,IR1,IR2,NTRY,IDMIN,IMAX,I,MHEP,
+     & IM,JM,KM,IB
+      LOGICAL DIQK
+      EXTERNAL HWR,HWRINT
+      DIQK(ID)=ID.GT.3.AND.ID.LT.10
+      IF (IERROR.NE.0) RETURN
+      ID2=0
+      EM0=PHEP(5,JCL)
+      IR1=NCLDK(LOCN(ID1,ID3))
+      EM1=RMIN(ID1,ID3)
+      IF (ABS(EM0-EM1).LT.0.001) THEN
+C---SINGLE-HADRON CLUSTER
+        NHEP=NHEP+1
+        IF (NHEP.GT.NMXHEP) CALL HWWARN('HWCHAD',100,*999)
+        IDHW(NHEP)=IR1
+        IDHEP(NHEP)=IDPDG(IR1)
+        ISTHEP(NHEP)=191
+        JDAHEP(1,JCL)=NHEP
+        JDAHEP(2,JCL)=NHEP
+        CALL HWVEQU(5,PHEP(1,JCL),PHEP(1,NHEP))
+        CALL HWVSUM(4,VHEP(1,JCL),VTXPIP,VHEP(1,NHEP))
+      ELSE
+        NTRY=0
+        IDMIN=1
+        EMLOW=RMIN(ID1,1)+RMIN(1,ID3)
+        EMADU=RMIN(ID1,2)+RMIN(2,ID3)
+        IF (EMADU.LT.EMLOW) THEN
+          IDMIN=2
+          EMLOW=EMADU
+        ENDIF
+        EMSQ=EM0**2
+        PCMAX=EMSQ-EMLOW**2
+        IF (PCMAX.GE.ZERO) THEN
+C---SET UP TWO QUARK-ANTIQUARK PAIRS OR A
+C   QUARK-DIQUARK AND AN ANTIDIQUARK-ANTIQUARK
+          PCMAX=PCMAX*(EMSQ-(RMIN(ID1,IDMIN)-RMIN(IDMIN,ID3))**2)
+          IMAX=12
+          IF (DIQK(ID1).OR.DIQK(ID3)) IMAX=3
+          DO 10 I=3,IMAX
+          IF (EM0.LT.RMIN(ID1,I)+RMIN(I,ID3)) GOTO 20
+  10      CONTINUE
+          I=IMAX+1
+  20      ID2=HWRINT(1,I-1)
+          IF (PWT(ID2).NE.ONE) THEN
+            IF (PWT(ID2).LT.HWR()) GOTO 20
+          ENDIF
+C---PICK TWO PARTICLES WITH THESE QUANTUM NUMBERS
+          NTRY=NTRY+1
+  30      IR1=LOCN(ID1,ID2)+INT(RESN(ID1,ID2)*HWR())
+          IF (CLDKWT(IR1).LT.HWR()) GOTO 30
+          IR1=NCLDK(IR1)
+  40      IR2=LOCN(ID2,ID3)+INT(RESN(ID2,ID3)*HWR())
+          IF (CLDKWT(IR2).LT.HWR()) GOTO 40
+          IR2=NCLDK(IR2)
+          EM1=RMASS(IR1)
+          EM2=RMASS(IR2)
+          PCM=EMSQ-(EM1+EM2)**2
+          IF (PCM.GT.ZERO) GOTO 70
+  50      IF (NTRY.LE.NDTRY) GOTO 20
+C---CAN'T FIND A DECAY MODE - CHOOSE LIGHTEST
+  60      ID2=HWRINT(1,2)
+          IR1=NCLDK(LOCN(ID1,ID2))
+          IR2=NCLDK(LOCN(ID2,ID3))
+          EM1=RMASS(IR1)
+          EM2=RMASS(IR2)
+          PCM=EMSQ-(EM1+EM2)**2
+          IF (PCM.GT.ZERO) GOTO 70
+          NTRY=NTRY+1
+          IF (NTRY.LE.NDTRY+50) GOTO 60
+          CALL HWWARN('HWCHAD',101,*999)
+C---DECAY IS ALLOWED
+  70      PCM=PCM*(EMSQ-(EM1-EM2)**2)
+          IF (NTRY.GT.NCTRY) GOTO 80
+          PTEST=PCM*SWTEF(IR1)*SWTEF(IR2)
+          IF (PTEST.LT.PCMAX*HWR()**2) GOTO 20
+        ELSE
+C---ALLOW DECAY BY PI0 EMISSION IF ONLY POSSIBILITY
+          ID2=1
+          IR2=NCLDK(LOCN(1,1))
+          EM2=RMASS(IR2)
+          PCM=(EMSQ-(EM1+EM2)**2)*(EMSQ-(EM1-EM2)**2)
+        ENDIF
+C---DECAY IS CHOSEN.  GENERATE DECAY MOMENTA
+C   AND PUT PARTICLES IN /HEPEVT/
+  80    IF (PCM.LT.ZERO) CALL HWWARN('HWCHAD',102,*999)
+        PCM=0.5*SQRT(PCM)/EM0
+        MHEP=NHEP+1
+        NHEP=NHEP+2
+        IF (NHEP.GT.NMXHEP) CALL HWWARN('HWCHAD',103,*999)
+        PHEP(5,MHEP)=EM1
+        PHEP(5,NHEP)=EM2
+C Decide if cluster contains a b-(anti)quark or not
+        IF (ID1.EQ.11.OR.ID2.EQ.11.OR.ID3.EQ.11) THEN
+          IB=2
+        ELSE
+          IB=1
+        ENDIF
+        IF (CLDIR(IB).NE.0) THEN
+          DO 110 IM=1,2
+            JM=JMOHEP(IM,JCL)
+            IF (JM.EQ.0) GOTO 110
+            IF (ISTHEP(JM).NE.158) GOTO 110
+C   LOOK FOR PARENT PARTON
+            DO 100 KM=JMOHEP(1,JM)+1,JM
+              IF (ISTHEP(KM).EQ.2) THEN
+                IF (JDAHEP(1,KM).EQ.JM) THEN
+C   FOUND PARENT PARTON
+                  IF (IDHW(KM).NE.13) THEN
+C   FIND ITS DIRECTION IN CLUSTER CMF
+                   CALL HWULOF(PHEP(1,JCL),PHEP(1,KM),PP)
+                   PCQK=PP(1)**2+PP(2)**2+PP(3)**2
+                   IF (PCQK.GT.ZERO) THEN
+                    PCQK=SQRT(PCQK)
+                    IF (CLSMR(IB).GT.ZERO) THEN
+C   DO GAUSSIAN SMEARING OF DIRECTION
+  90                 CT=ONE+CLSMR(IB)*LOG(HWR())
+                     IF (CT.LT.-ONE) GOTO 90
+                     ST=ONE-CT*CT
+                     IF (ST.GT.ZERO) ST=SQRT(ST)
+                     CALL HWRAZM( ONE,CX,SX)
+                     CALL HWUROT(PP,CX,SX,RMAT)
+                     PP(1)=ZERO
+                     PP(2)=PCQK*ST
+                     PP(3)=PCQK*CT
+                     CALL HWUROB(RMAT,PP,PP)
+                    ENDIF
+                    PCQK=PCM/PCQK
+                    IF (IM.EQ.2) PCQK=-PCQK
+                    CALL HWVSCA(3,PCQK,PP,PHEP(1,MHEP))
+                    PHEP(4,MHEP)=SQRT(PHEP(5,MHEP)**2+PCM**2)
+                    CALL HWULOB(PHEP(1,JCL),PHEP(1,MHEP),PHEP(1,MHEP))
+                    CALL HWVDIF(4,PHEP(1,JCL),PHEP(1,MHEP),PHEP(1,NHEP))
+                    GOTO 130
+                   ENDIF
+                  ENDIF
+                  GOTO 120
+                ENDIF
+              ELSEIF (ISTHEP(KM).GT.140) THEN
+C   FINISHED THIS JET
+                GOTO 110
+              ENDIF
+ 100        CONTINUE
+ 110      CONTINUE
+        ENDIF
+ 120    CALL HWDTWO(PHEP(1,JCL),PHEP(1,MHEP),PHEP(1,NHEP),
+     &              PCM,TWO,.TRUE.)
+ 130    IDHW(MHEP)=IR1
+        IDHW(NHEP)=IR2
+        IDHEP(MHEP)=IDPDG(IR1)
+        IDHEP(NHEP)=IDPDG(IR2)
+        ISTHEP(MHEP)=192
+        ISTHEP(NHEP)=192
+        JMOHEP(1,MHEP)=JCL
+C---SECOND MOTHER OF HADRON IS JET
+        JMOHEP(2,MHEP)=JMOHEP(1,JMOHEP(1,JCL))
+        JDAHEP(1,JCL)=MHEP
+        JDAHEP(2,JCL)=NHEP
+C---SMEAR HADRON POSITIONS
+        HPSMR=GEV2MM/PHEP(5,JCL)
+        DO I=1,4
+          VHEP(I,MHEP)=HWRGAU(I,ZERO,HPSMR)
+        ENDDO
+        VHEP(4,MHEP)=ABS(VHEP(4,MHEP))
+     &           +SQRT(HWVDOT(3,VHEP(1,MHEP),VHEP(1,MHEP)))
+        CALL HWULB4(PHEP(1,JCL),VHEP(1,MHEP),VHEP(1,MHEP))
+        CALL HWVSUM(4,VHEP(1,JCL),VHEP(1,MHEP),VHEP(1,MHEP))
+        CALL HWVSUM(4,VTXPIP,VHEP(1,MHEP),VHEP(1,MHEP))
+        DO I=1,4
+          VHEP(I,NHEP)=HWRGAU(I,ZERO,HPSMR)
+        ENDDO
+        VHEP(4,NHEP)=ABS(VHEP(4,NHEP))
+     &           +SQRT(HWVDOT(3,VHEP(1,NHEP),VHEP(1,NHEP)))
+        CALL HWULB4(PHEP(1,JCL),VHEP(1,NHEP),VHEP(1,NHEP))
+        CALL HWVSUM(4,VHEP(1,JCL),VHEP(1,NHEP),VHEP(1,NHEP))
+        CALL HWVSUM(4,VTXPIP,VHEP(1,NHEP),VHEP(1,NHEP))
+      ENDIF
+      ISTHEP(JCL)=180+MOD(ISTHEP(JCL),10)
+      JMOHEP(1,NHEP)=JCL
+      JMOHEP(2,NHEP)=JMOHEP(1,JMOHEP(1,JCL))
+  999 END
+CDECK  ID>, HWDBOS.
+*CMZ :-        -23/05/96  18.34.17  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDBOS(IBOSON)
+C-----------------------------------------------------------------------
+C     DECAY GAUGE BOSONS (ALREADY FOUND BY HWDHAD)
+C     USES SPIN DENSITY MATRIX IN RHOHEP (1ST CMPT=>-VE,2=>LONG,3=>+VE)
+C     IF BOSON CAME FROM HIGGS DECAY, GIVE BOTH THE SAME HELICITY (EPR)
+C     IF BOSON CAME FROM W+1JET, GIVE IT THE CORRECT DECAY CORRELATIONS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,HWRUNI,HWUPCM,HWULDO,R(3,3),CV,CA,BR,PCM,
+     & PBOS(5),PMAX,PROB,RRLL,RLLR
+      INTEGER HWRINT,IBOS,IBOSON,IPAIR,ICMF,IOPT,IHEL,IMOTH,
+     & I,IQRK,IANT,ID,IQ
+      LOGICAL QUARKS
+      EXTERNAL HWR,HWRUNI,HWUPCM,HWULDO,HWRINT
+      IBOS=IBOSON
+      IF (IDHW(IBOS).LT.198.OR.IDHW(IBOS).GT.200)
+     &  CALL HWWARN('HWDBOS',101,*999)
+      QUARKS=.FALSE.
+C---SEE IF IT IS PART OF A PAIR
+      IMOTH=JMOHEP(1,IBOS)
+      IPAIR=JMOHEP(2,IBOS)
+      ICMF=JMOHEP(1,IBOS)
+      IF (IDHW(ICMF).EQ.IDHW(IBOS).AND.ISTHEP(ICMF)/10.EQ.12)
+     &  ICMF=JMOHEP(1,ICMF)
+      IOPT=0
+      IF (IPAIR.NE.0) THEN
+        IF (JMOHEP(2,IPAIR).NE.IBOS.OR.
+     &    IDHW(IPAIR).LT.198.OR.IDHW(IPAIR).GT.200) IPAIR=0
+      ENDIF
+      IF (IPAIR.GT.0) IOPT=1
+C---SELECT DECAY PRODUCTS
+   10 CALL HWDBOZ(IDHW(IBOS),IDN(1),IDN(2),CV,CA,BR,IOPT)
+C---V + 1JET DECAYS ARE NOW HANDLED HERE !
+      IF (IPRO.EQ.21) THEN
+        IQRK=IDHW(JMOHEP(1,ICMF))
+        IANT=IDHW(JMOHEP(2,ICMF))
+        IF (IQRK.EQ.13 .AND. IANT.LE.6) THEN
+          IQRK=JMOHEP(2,ICMF)
+          IANT=JDAHEP(2,ICMF)
+        ELSEIF (IQRK.EQ.13) THEN
+          IQRK=JDAHEP(2,ICMF)
+          IANT=JMOHEP(2,ICMF)
+        ELSEIF (IANT.EQ.13 .AND. IQRK.LE.6) THEN
+          IQRK=JMOHEP(1,ICMF)
+          IANT=JDAHEP(2,ICMF)
+        ELSEIF (IANT.EQ.13) THEN
+          IQRK=JDAHEP(2,ICMF)
+          IANT=JMOHEP(1,ICMF)
+        ELSEIF (IQRK.GT.IANT) THEN
+          IQRK=JMOHEP(2,ICMF)
+          IANT=JMOHEP(1,ICMF)
+        ELSE
+          IQRK=JMOHEP(1,ICMF)
+          IANT=JMOHEP(2,ICMF)
+        ENDIF
+        PHEP(5,NHEP+1)=RMASS(IDN(1))
+        PHEP(5,NHEP+2)=RMASS(IDN(2))
+        PCM=HWUPCM(PHEP(5,IBOS),PHEP(5,NHEP+1),PHEP(5,NHEP+2))
+        IF (PCM.LT.ZERO) CALL HWWARN('HWDBOS',103,*999)
+        IF (IDHW(IBOS).EQ.200) THEN
+          ID=IDN(1)
+          IF (ID.GT.120) ID=ID-110
+          IQ=IDHW(IQRK)
+          IF (IQ.GT.6) IQ=IQ-6
+          RRLL=(VFCH(IQ,1)**2+AFCH(IQ,1)**2)*
+     $         (VFCH(ID,1)**2+AFCH(ID,1)**2)
+     $         +4*VFCH(IQ,1)*AFCH(IQ,1)*
+     $         VFCH(ID,1)*AFCH(ID,1)
+          RLLR=(VFCH(IQ,1)**2+AFCH(IQ,1)**2)*
+     $         (VFCH(ID,1)**2+AFCH(ID,1)**2)
+     $         -4*VFCH(IQ,1)*AFCH(IQ,1)*
+     $         VFCH(ID,1)*AFCH(ID,1)
+        ELSE
+          RRLL=1
+          RLLR=0
+        ENDIF
+        PMAX=(RRLL+RLLR)
+     &      *(HWULDO(PHEP(1,IANT),PHEP(1,IBOS))**2+
+     &        HWULDO(PHEP(1,IQRK),PHEP(1,IBOS))**2)
+ 1      CALL HWDTWO(PHEP(1,IBOS),PHEP(1,NHEP+1),PHEP(1,NHEP+2),
+     &              PCM,TWO,.TRUE.)
+        PROB=RRLL*(HWULDO(PHEP(1,IANT),PHEP(1,NHEP+1))**2+
+     &             HWULDO(PHEP(1,IQRK),PHEP(1,NHEP+2))**2)+
+     &       RLLR*(HWULDO(PHEP(1,IANT),PHEP(1,NHEP+2))**2+
+     &             HWULDO(PHEP(1,IQRK),PHEP(1,NHEP+1))**2)
+        IF (PROB.GT.PMAX.OR.PROB.LT.ZERO)
+     &   CALL HWWARN('HWDBOS',104,*999)
+        IF (PMAX*HWR().GT.PROB) GOTO 1
+      ELSE
+C---SELECT HELICITY, UNLESS IT IS THE SECOND OF A HIGGS DECAY (EPR)
+      IF (IPAIR.NE.IBOS .OR. IDHW(ICMF).NE.201) THEN
+      IF (RHOHEP(1,IBOS)+RHOHEP(2,IBOS)+RHOHEP(3,IBOS).LE.ZERO) THEN
+C---COPY PARENT HELICITY IF IT WAS A GAUGE BOSON
+        IF (IDHW(IMOTH).GE.198.AND.IDHW(IMOTH).LE.200) THEN
+          CALL HWVEQU(3,RHOHEP(1,IMOTH),RHOHEP(1,IBOS))
+          IF (RHOHEP(1,IBOS)+RHOHEP(2,IBOS)+RHOHEP(3,IBOS).GT.ZERO)
+     &    GOTO 20
+C---MAY BE FROM A SUSY DECAY
+        ELSEIF (ABS(IDHEP(IMOTH)).LT.1000000) THEN
+          CALL HWWARN('HWDBOS',1,*999)
+        ENDIF
+        RHOHEP(1,IBOS)=1.
+        RHOHEP(2,IBOS)=1.
+        RHOHEP(3,IBOS)=1.
+      ENDIF
+ 20   IHEL=HWRINT(1,3)
+      IF (HWR().GT.RHOHEP(IHEL,IBOS)) GOTO 20
+      ENDIF
+C---SELECT DIRECTION OF FERMION
+ 30   COSTH=HWRUNI(0,-ONE,ONE)
+      IF (IHEL.EQ.1 .AND. (ONE+COSTH)**2.LT.HWR()*FOUR) GOTO 30
+      IF (IHEL.EQ.2 .AND. (ONE-COSTH**2).LT.HWR()     ) GOTO 30
+      IF (IHEL.EQ.3 .AND. (ONE-COSTH)**2.LT.HWR()*FOUR) GOTO 30
+C---GENERATE DECAY RELATIVE TO Z-AXIS
+      PHEP(5,NHEP+1)=RMASS(IDN(1))
+      PHEP(5,NHEP+2)=RMASS(IDN(2))
+      PCM=HWUPCM(PHEP(5,IBOS),PHEP(5,NHEP+1),PHEP(5,NHEP+2))
+      IF (PCM.LT.ZERO) CALL HWWARN('HWDBOS',102,*999)
+      CALL HWRAZM(PCM*SQRT(1-COSTH**2),PHEP(1,NHEP+1),PHEP(2,NHEP+1))
+      PHEP(3,NHEP+1)=PCM*COSTH
+      PHEP(4,NHEP+1)=SQRT(PHEP(5,NHEP+1)**2+PCM**2)
+C---ROTATE SO THAT Z-AXIS BECOMES BOSON'S DIRECTION IN ORIGINAL CM FRAME
+      CALL HWULOF(PHEP(1,ICMF),PHEP(1,IBOS),PBOS)
+      CALL HWUROT(PBOS, ONE,ZERO,R)
+      CALL HWUROB(R,PHEP(1,NHEP+1),PHEP(1,NHEP+1))
+C---BOOST BACK TO LAB
+      CALL HWULOB(PHEP(1,IBOS),PHEP(1,NHEP+1),PHEP(1,NHEP+1))
+      CALL HWVDIF(4,PHEP(1,IBOS),PHEP(1,NHEP+1),PHEP(1,NHEP+2))
+      ENDIF
+C---STATUS, IDs AND POINTERS
+      ISTHEP(IBOS)=195
+      DO 50 I=1,2
+        ISTHEP(NHEP+I)=193
+        IDHW(NHEP+I)=IDN(I)
+        IDHEP(NHEP+I)=IDPDG(IDN(I))
+        JDAHEP(I,IBOS)=NHEP+I
+        JMOHEP(1,NHEP+I)=IBOS
+        JMOHEP(2,NHEP+I)=JMOHEP(1,IBOS)
+ 50   CONTINUE
+      NHEP=NHEP+2
+      IF (IDN(1).LE.12) THEN
+        ISTHEP(NHEP-1)=113
+        ISTHEP(NHEP)=114
+        JMOHEP(2,NHEP)=NHEP-1
+        JDAHEP(2,NHEP)=NHEP-1
+        JMOHEP(2,NHEP-1)=NHEP
+        JDAHEP(2,NHEP-1)=NHEP
+        QUARKS=.TRUE.
+      ENDIF
+C---IF FIRST OF A PAIR, DO SECOND DECAY
+      IF (IPAIR.NE.0 .AND. IPAIR.NE.IBOS) THEN
+        IBOS=IPAIR
+        GOTO 10
+      ENDIF
+C---IF QUARK DECAY, HADRONIZE
+      IF (QUARKS) THEN
+        EMSCA=PHEP(5,IBOS)
+        CALL HWBGEN
+        CALL HWDHOB
+        CALL HWCFOR
+        CALL HWCDEC
+      ENDIF
+ 999  END
+CDECK  ID>, HWDBOZ.
+*CMZ :-        -29/04/91  18.00.03  by  Federico Carminati
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDBOZ(IDBOS,IFER,IANT,CV,CA,BR,IOPT)
+C-----------------------------------------------------------------------
+C     CHOOSE DECAY MODE OF BOSON
+C     IOPT=2 TO RESET COUNTERS, 1 FOR BOSON PAIR, 0 FOR ANY OTHERS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,BRMODE(12,3),CV,CA,BR,BRLST,BRCOM,FACZ,
+     & FACW
+      INTEGER HWRINT,IDBOS,IDEC,IDMODE(2,12,3),IFER,IANT,IOPT,I1,I2,
+     & I1LST,I2LST,NWGLST,NUMDEC,NPAIR,MODTMP,JFER
+      LOGICAL GENLST
+      EXTERNAL HWR,HWRINT
+      SAVE FACW,FACZ,NWGLST,GENLST,NUMDEC,NPAIR,I1LST,I2LST,BRLST
+      DATA NWGLST,GENLST,NPAIR/-1,.FALSE.,0/
+C---STORE THE DECAY MODES (FERMION FIRST)
+      DATA IDMODE/  2,  7,  4,  9,  6, 11,  2,  9,  4,  7,
+     &            122,127,124,129,126,131,8*0,
+     &              1,  8,  3, 10,  5, 12,  3,  8,  1, 10,
+     &            121,128,123,130,125,132,8*0,
+     &              1,  7,  2,  8,  3,  9,  4, 10,  5, 11,  6, 12,
+     &            121,127,123,129,125,131,122,128,124,130,126,132/
+C---STORE THE BRANCHING RATIOS TO THESE MODES
+      DATA BRMODE/0.321,0.321,0.000,0.017,0.017,0.108,0.108,0.108,4*0.0,
+     &            0.321,0.321,0.000,0.017,0.017,0.108,0.108,0.108,4*0.0,
+     &            0.154,0.120,0.154,0.120,0.152,0.000,
+     &            0.033,0.033,0.033,0.067,0.067,0.067/
+C---FACTORS FOR CV AND CA FOR W AND Z
+      DATA FACW,FACZ/2*0.0/
+      IF (FACZ.EQ.ZERO) FACZ=SQRT(SWEIN)
+      IF (FACW.EQ.ZERO) FACW=0.5/SQRT(2D0)
+      IF (IDBOS.LT.198.OR.IDBOS.GT.200) CALL HWWARN('HWDBOZ',101,*999)
+C---IF THIS IS A NEW EVENT SINCE LAST TIME, ZERO COUNTERS
+      IF (NWGTS.NE.NWGLST .OR.(GENEV.NEQV.GENLST).OR. IOPT.EQ.2) THEN
+        NPAIR=0
+        NUMDEC=0
+        NWGLST=NWGTS
+        GENLST=GENEV
+        IF (IOPT.EQ.2) RETURN
+      ENDIF
+      NUMDEC=NUMDEC+1
+      IF (NUMDEC.GT.MODMAX) CALL HWWARN('HWDBOZ',102,*999)
+C---IF PAIR OPTION SPECIFIED FOR THE FIRST TIME, MAKE CHOICE
+      IF (IOPT.EQ.1) THEN
+        IF (NUMDEC.GT.MODMAX-1) CALL HWWARN('HWDBOZ',103,*999)
+        IF (NPAIR.EQ.0) THEN
+          IF (HWR().GT.HALF) THEN
+            MODTMP=MODBOS(NUMDEC+1)
+            MODBOS(NUMDEC+1)=MODBOS(NUMDEC)
+            MODBOS(NUMDEC)=MODTMP
+          ENDIF
+          NPAIR=NUMDEC
+        ELSE
+          NPAIR=0
+        ENDIF
+      ENDIF
+C---SELECT USER'S CHOICE
+      IF (IDBOS.EQ.200) THEN
+        IF (MODBOS(NUMDEC).EQ.1) THEN
+          I1=1
+          I2=6
+        ELSEIF (MODBOS(NUMDEC).EQ.2) THEN
+          I1=7
+          I2=7
+        ELSEIF (MODBOS(NUMDEC).EQ.3) THEN
+          I1=8
+          I2=8
+        ELSEIF (MODBOS(NUMDEC).EQ.4) THEN
+          I1=9
+          I2=9
+        ELSEIF (MODBOS(NUMDEC).EQ.5) THEN
+          I1=7
+          I2=8
+        ELSEIF (MODBOS(NUMDEC).EQ.6) THEN
+          I1=10
+          I2=12
+        ELSEIF (MODBOS(NUMDEC).EQ.7) THEN
+          I1=5
+          I2=5
+        ELSE
+          I1=1
+          I2=12
+        ENDIF
+      ELSE
+        IF (MODBOS(NUMDEC).EQ.1) THEN
+          I1=1
+          I2=5
+        ELSEIF (MODBOS(NUMDEC).EQ.2) THEN
+          I1=6
+          I2=6
+        ELSEIF (MODBOS(NUMDEC).EQ.3) THEN
+          I1=7
+          I2=7
+        ELSEIF (MODBOS(NUMDEC).EQ.4) THEN
+          I1=8
+          I2=8
+        ELSEIF (MODBOS(NUMDEC).EQ.5) THEN
+          I1=6
+          I2=7
+        ELSE
+          I1=1
+          I2=8
+        ENDIF
+      ENDIF
+ 10   IDEC=HWRINT(I1,I2)
+      IF (HWR().GT.BRMODE(IDEC,IDBOS-197).AND.I1.NE.I2) GOTO 10
+      IFER=IDMODE(1,IDEC,IDBOS-197)
+      IANT=IDMODE(2,IDEC,IDBOS-197)
+C---CALCULATE BRANCHING RATIO
+C   (RESULT IS NOT WELL-DEFINED AFTER THE FIRST CALL OF A PAIR)
+      BR=0
+      DO 20 IDEC=I1,I2
+ 20     BR=BR+BRMODE(IDEC,IDBOS-197)
+      IF (IOPT.EQ.1) THEN
+        IF (NPAIR.NE.0) THEN
+          I1LST=I1
+          I2LST=I2
+          BRLST=BR
+        ELSE
+          BRCOM=0
+          DO 30 IDEC=MAX(I1,I1LST),MIN(I2,I2LST)
+ 30         BRCOM=BRCOM+BRMODE(IDEC,IDBOS-197)
+          BR=2*BR*BRLST - BRCOM**2
+        ENDIF
+      ENDIF
+C---SET UP VECTOR AND AXIAL VECTOR COUPLINGS (NORMALIZED TO THE
+C   CONVENTION WHERE THE WEAK CURRENT IS G*(CV-CA*GAM5) )
+      IF (IDBOS.EQ.200) THEN
+        IF (IFER.LE.6) THEN
+C Quark couplings
+           CV=VFCH(IFER,1)
+           CA=AFCH(IFER,1)
+        ELSE
+C lepton couplings
+           JFER=IFER-110
+           CV=VFCH(JFER,1)
+           CA=AFCH(JFER,1)
+        ENDIF
+        CV=CV * FACZ
+        CA=CA * FACZ
+      ELSE
+        CV=FACW
+        CA=FACW
+      ENDIF
+ 999  END
+CDECK  ID>, HWDCHK.
+*CMZ :-        -27/07/99  13.33.03  by  Mike Seymour
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDCHK(IDKY,L,*)
+C-----------------------------------------------------------------------
+C     Checks line L of decay table is compatible with decay of particle
+C     IDKY, tidies up the line and sets NPRODS.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION EPS,QS,Q,DM
+      INTEGER IDKY,L,IFAULT,I,ID,J
+      PARAMETER (EPS=1.D-6)
+      IF (VTOCDK(IDKY).AND.VTORDK(IDKY)) RETURN 1
+      IFAULT=0
+      QS=FLOAT(ICHRG(IDKY))
+      IF (IDKY.LE.12.OR.(IDKY.GE.109.AND.IDKY.LE.120)
+     &              .OR.(IDKY.GE.209.AND.IDKY.LE.220)
+     &              .OR.(IDKY.GE.401.AND.IDKY.LE.424)) QS=QS/3.
+      DM=RMASS(IDKY)
+      NPRODS(L)=0
+      DO 10 I=1,5
+      ID=IDKPRD(I,L)
+      IF (ID.LT.0.OR.ID.EQ.20.OR.ID.GT.NRES) THEN
+        WRITE(6,20) L,RNAME(IDKY),(RNAME(IDKPRD(J,L)),J=1,5)
+        IFAULT=IFAULT+1
+      ELSEIF (ID.NE.0) THEN
+        IF (VTORDK(ID)) THEN
+          WRITE(6,30) L,RNAME(IDKY),(RNAME(IDKPRD(J,L)),J=1,5),RNAME(ID)
+          IFAULT=IFAULT+1
+        ENDIF
+        NPRODS(L)=NPRODS(L)+1
+        IDKPRD(NPRODS(L),L)=ID
+        Q=FLOAT(ICHRG(ID))
+        IF (ID.LE.12.OR.(ID.GE.109.AND.ID.LE.120)
+     &              .OR.(ID.GE.209.AND.ID.LE.220)
+     &              .OR.(ID.GE.401.AND.ID.LE.424)) Q=Q/3.
+        QS=QS-Q
+        DM=DM-RMASS(ID)
+      ENDIF
+  10  CONTINUE
+C print any warnings
+      IF (NPRODS(L).EQ.0) THEN
+        WRITE(6,20) L,RNAME(IDKY),(RNAME(IDKPRD(I,L)),I=1,5)
+        IFAULT=IFAULT+1
+      ELSE
+        IF (ABS(QS).GT.EPS) THEN
+          WRITE(6,40) L,RNAME(IDKY),(RNAME(IDKPRD(I,L)),I=1,5),QS
+          IFAULT=IFAULT+1
+        ENDIF
+        IF (DM.LT.ZERO) THEN
+          WRITE(6,50) L,RNAME(IDKY),(RNAME(IDKPRD(I,L)),I=1,5),DM
+          IFAULT=IFAULT+1
+        ENDIF
+      ENDIF
+  20  FORMAT(1X,'Line ',I4,' decay: ',A8,' --> ',4(A8,1X),A8/
+     &       1X,'contains no or unrecognised decay product(s)')
+  30  FORMAT(1X,'Line ',I4,' decay: ',A8,' --> ',4(A8,1X),A8/
+     &       1X,'contains decay product ',A8,' which is vetoed')
+  40  FORMAT(1X,'Line ',I4,' decay: ',A8,' --> ',4(A8,1X),A8/
+     &       1X,'violates charge conservation, Qin-Qout= ',F6.3)
+  50  FORMAT(1X,'Line ',I4,' decay: ',A8,' --> ',4(A8,1X),A8/
+     &       1X,'is kinematically not allowed, Min-Mout= ',F10.3)
+      IF (IFAULT.NE.0) THEN
+        RETURN 1
+      ELSE
+        RETURN
+      ENDIF
+      END
+CDECK  ID>, HWDCLE.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Luca Stanco
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDCLE(IHEP)
+C-----------------------------------------------------------------------
+C INTERFACE TO QQ-CLEO MONTE CARLO (LS 11/12/91)
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,IIHEP,NHEPHF,QQLMAT
+      LOGICAL QQLERR
+      CHARACTER*8 NAME
+      EXTERNAL QQLMAT
+C---QQ-CLEO COMMON'S
+C***                 MCPARS.INC
+      INTEGER MCTRK, NTRKS, MCVRTX, NVTXS, MCHANS, MCDTRS, MPOLQQ
+      INTEGER MCNUM, MCSTBL, MCSTAB, MCTLQQ, MDECQQ
+      INTEGER MHLPRB, MHLLST, MHLANG, MCPLST, MFDECA
+      PARAMETER (MCTRK = 512)
+      PARAMETER (NTRKS = MCTRK)
+      PARAMETER (MCVRTX = 256)
+      PARAMETER (NVTXS = MCVRTX)
+      PARAMETER (MCHANS = 4000)
+      PARAMETER (MCDTRS = 8000)
+      PARAMETER (MPOLQQ = 300)
+      PARAMETER (MCNUM = 500)
+      PARAMETER (MCSTBL = 40)
+      PARAMETER (MCSTAB = 512)
+      PARAMETER (MCTLQQ = 100)
+      PARAMETER (MDECQQ = 300)
+      PARAMETER (MHLPRB = 500)
+      PARAMETER (MHLLST = 1000)
+      PARAMETER (MHLANG = 500)
+      PARAMETER (MCPLST = 200)
+      PARAMETER (MFDECA = 5)
+C***                 MCPROP.INC
+      REAL AMASS, CHARGE, CTAU, SPIN, RWIDTH, RMASMN, RMASMX
+      REAL RMIXPP, RCPMIX
+      INTEGER NPMNQQ, NPMXQQ, IDMC, INVMC, LPARTY, CPARTY
+      INTEGER IMIXPP, ICPMIX
+      COMMON/MCMAS1/
+     *       NPMNQQ, NPMXQQ,
+     *       AMASS(-20:MCNUM), CHARGE(-20:MCNUM), CTAU(-20:MCNUM),
+     *       IDMC(-20:MCNUM), SPIN(-20:MCNUM),
+     *       RWIDTH(-20:MCNUM), RMASMN(-20:MCNUM), RMASMX(-20:MCNUM),
+     *       LPARTY(-20:MCNUM), CPARTY(-20:MCNUM),
+     *       IMIXPP(-20:MCNUM), RMIXPP(-20:MCNUM),
+     *       ICPMIX(-20:MCNUM), RCPMIX(-20:MCNUM),
+     *       INVMC(0:MCSTBL)
+C
+      INTEGER NPOLQQ, IPOLQQ
+      COMMON/MCPOL1/
+     *       NPOLQQ, IPOLQQ(5,MPOLQQ)
+C
+      CHARACTER QNAME*10, PNAME*10
+      COMMON/MCNAMS/
+     *       QNAME(37), PNAME(-20:MCNUM)
+C
+C***                 MCCOMS.INC
+      INTEGER NCTLQQ, NDECQQ, IVRSQQ, IORGQQ, IRS1QQ
+      INTEGER IEVTQQ, IRUNQQ, IBMRAD
+      INTEGER NTRKMC, QQNTRK, NSTBMC, NSTBQQ, NCHGMC, NCHGQQ
+      INTEGER IRANQQ, IRANMC, IRANCC, IRS2QQ
+      INTEGER IPFTQQ, IPCDQQ, IPRNTV, ITYPEV, IDECSV, IDAUTV
+      INTEGER ISTBMC, NDAUTV
+      INTEGER IVPROD, IVDECA
+      REAL BFLDQQ
+      REAL ENERQQ, BEAMQQ, BMPSQQ, BMNGQQ, EWIDQQ, BWPSQQ, BWNGQQ
+      REAL BPOSQQ, BSIZQQ
+      REAL ECM, P4CMQQ, P4PHQQ, ENERNW, BEAMNW, BEAMP, BEAMN
+      REAL PSAV, P4QQ, HELCQQ
+      CHARACTER DATEQQ*20, TIMEQQ*20, FOUTQQ*80, FCTLQQ*80, FDECQQ*80
+      CHARACTER FGEOQQ*80
+      CHARACTER CCTLQQ*80, CDECQQ*80
+C
+      COMMON/MCCM1A/
+     *   NCTLQQ, NDECQQ, IVRSQQ, IORGQQ, IRS1QQ(3), BFLDQQ,
+     *   ENERQQ, BEAMQQ, BMPSQQ, BMNGQQ, EWIDQQ, BWPSQQ, BWNGQQ,
+     *   BPOSQQ(3), BSIZQQ(3),
+     *   IEVTQQ, IRUNQQ,
+     *   IBMRAD, ECM, P4CMQQ(4), P4PHQQ(4),
+     *   ENERNW, BEAMNW, BEAMP, BEAMN,
+     *   NTRKMC, QQNTRK, NSTBMC, NSTBQQ, NCHGMC, NCHGQQ,
+     *   IRANQQ(2), IRANMC(2), IRANCC(2), IRS2QQ(5),
+     *   IPFTQQ(MCTRK), IPCDQQ(MCTRK), IPRNTV(MCTRK), ITYPEV(MCTRK,2),
+     *   IDECSV(MCTRK), IDAUTV(MCTRK), ISTBMC(MCTRK), NDAUTV(MCTRK),
+     *   IVPROD(MCTRK), IVDECA(MCTRK),
+     *   PSAV(MCTRK,4), HELCQQ(MCTRK), P4QQ(4,MCTRK)
+C
+      COMMON/MCCM1B/
+     *   DATEQQ, TIMEQQ, FOUTQQ, FCTLQQ, FDECQQ, FGEOQQ,
+     *   CCTLQQ(MCTLQQ), CDECQQ(MDECQQ)
+      INTEGER IDSTBL
+      COMMON/MCCM1C/
+     *   IDSTBL(MCSTAB)
+C
+      INTEGER IFINAL(MCTRK), IFINSV(MCSTAB), NFINAL
+      EQUIVALENCE (IFINAL,ISTBMC), (IFINSV,IDSTBL), (NFINAL,NSTBMC)
+C
+      INTEGER NVRTX, ITRKIN, NTRKOU, ITRKOU, IVKODE
+      REAL XVTX, TVTX, RVTX
+      COMMON/MCCM2/
+     *   NVRTX, XVTX(MCVRTX,3), TVTX(MCVRTX), RVTX(MCVRTX),
+     *   ITRKIN(MCVRTX), NTRKOU(MCVRTX), ITRKOU(MCVRTX),
+     *   IVKODE(MCVRTX)
+C***                 MCGEN.INC
+      INTEGER QQIST,QQIFR,QQN,QQK,QQMESO,QQNC,QQKC,QQLASTN
+      REAL QQPUD,QQPS1,QQSIGM,QQMAS,QQPAR,QQCMIX,QQCND,QQBSPI,QQBSYM,QQP
+      REAL QQPC,QQCZF
+C
+      COMMON/DATA1/QQIST,QQIFR,QQPUD,QQPS1,QQSIGM,QQMAS(15),QQPAR(25)
+      COMMON/DATA2/QQCZF(15),QQMESO(36),QQCMIX(6,2)
+      COMMON/DATA3/QQCND(3)
+      COMMON/DATA5/QQBSPI(5),QQBSYM(3)
+      COMMON/JET/QQN,QQK(250,2),QQP(250,5),QQNC,QQKC(10),QQPC(10,4),
+     *  QQLASTN
+C---
+      IF(FSTEVT) THEN
+C---INITIALIZE QQ-CLEO
+        CALL QQINIT(QQLERR)
+        IF(QQLERR) CALL HWWARN('HWDEUR',500,*999)
+      ENDIF
+C---CONSTRUCT THE HADRON FOR QQ-CLEO
+C NOTE: THE IDPDG CODE IS PROVIDED THROUGH THE QQLMAT ROUTINE
+C       FROM THE CLEO PACKAGE (QQ-CLEO <--> IDPDG CODE TRANSFORMATION)
+      QQN=1
+      IDHEP(IHEP)=IDPDG(IDHW(IHEP))
+      QQK(1,1)=0
+      QQK(1,2)=QQLMAT(IDHEP(IHEP),1)
+      QQP(1,1)=PHEP(1,IHEP)
+      QQP(1,2)=PHEP(2,IHEP)
+      QQP(1,3)=PHEP(3,IHEP)
+      QQP(1,5)=AMASS(QQK(1,2))
+      QQP(1,4)=SQRT(QQP(1,5)**2+QQP(1,1)**2+QQP(1,2)**2+QQP(1,3)**2)
+C---LET QQ-CLEO DO THE JOB
+      QQNTRK=0
+      NVRTX=0
+      CALL DECADD(.FALSE.)
+C---UPDATE THE HERWIG TABLE : LOOP OVER QQN-CLEO FINAL PARTICLES
+      DO 40 IIHEP=1,QQN
+      NHEP=NHEP+1
+      ISTHEP(NHEP)=198
+      IF(ITYPEV(IIHEP,2).GE.0) ISTHEP(NHEP)=1
+      IDHEP(NHEP)=QQLMAT(ITYPEV(IIHEP,1),2)
+      CALL HWUIDT(1,IDHEP(NHEP),IDHW(NHEP),NAME)
+      IF(IIHEP.EQ.1) THEN
+        ISTHEP(IHEP)=199
+        JDAHEP(1,IHEP)=NHEP
+        JDAHEP(2,IHEP)=NHEP
+        ISTHEP(NHEP)=199
+        NHEPHF=NHEP
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=IHEP
+      ELSE
+        JMOHEP(1,NHEP)=IPRNTV(IIHEP)+NHEPHF-1
+        JMOHEP(2,NHEP)=NHEPHF
+      ENDIF
+      JDAHEP(1,NHEP)=0
+      JDAHEP(2,NHEP)=0
+      IF(NDAUTV(IIHEP).GT.0) THEN
+        JDAHEP(1,NHEP)=IDAUTV(IIHEP)+NHEPHF-1
+        JDAHEP(2,NHEP)=JDAHEP(1,NHEP)+NDAUTV(IIHEP)-1
+      ENDIF
+      PHEP(1,NHEP)=QQP(IIHEP,1)
+      PHEP(2,NHEP)=QQP(IIHEP,2)
+      PHEP(3,NHEP)=QQP(IIHEP,3)
+      PHEP(4,NHEP)=QQP(IIHEP,4)
+      PHEP(5,NHEP)=QQP(IIHEP,5)
+      VHEP(1,NHEP)=XVTX(IVPROD(IIHEP),1)
+      VHEP(2,NHEP)=XVTX(IVPROD(IIHEP),2)
+      VHEP(3,NHEP)=XVTX(IVPROD(IIHEP),3)
+      VHEP(4,NHEP)=0.
+   40 CONTINUE
+  999 END
+CDECK  ID>, HWDEUR.
+*CMZ :-        -28/01/92  12.34.44  by  Mike Seymour
+*-- Author :    Luca Stanco
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDEUR(IHEP)
+C-----------------------------------------------------------------------
+C INTERFACE TO EURODEC PACKAGE (LS 10/29/91)
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,IIHEP,NHEPHF,IEUPDG,IPDGEU
+      CHARACTER*8 NAME
+C---EURODEC COMMON'S : INITIAL INPUT
+      INTEGER EULUN0,EULUN1,EULUN2,EURUN,EUEVNT
+      CHARACTER*4 EUDATD,EUTIT
+      REAL AMINIE(12),EUWEI
+      COMMON/INPOUT/EULUN0,EULUN1,EULUN2
+      COMMON/FILNAM/EUDATD,EUTIT
+      COMMON/HVYINI/AMINIE
+      COMMON/RUNINF/EURUN,EUEVNT,EUWEI
+C---EURODEC WORKING COMMON'S
+      INTEGER NPMAX,NTMAX
+      PARAMETER (NPMAX=18,NTMAX=2000)
+      INTEGER EUNP,EUIP(NPMAX),EUPHEL(NPMAX),EUTEIL,EUINDX(NTMAX),
+     &    EUORIG(NTMAX),EUDCAY(NTMAX),EUTHEL(NTMAX)
+      REAL EUAPM(NPMAX),EUPCM(5,NPMAX),EUPVTX(3,NPMAX),EUPTEI(5,NTMAX),
+     &    EUSECV(3,NTMAX)
+      COMMON/MOMGEN/EUNP,EUIP,EUAPM,EUPCM,EUPHEL,EUPVTX
+      COMMON/RESULT/EUTEIL,EUPTEI,EUINDX,EUORIG,EUDCAY,EUTHEL,EUSECV
+C---EURODEC COMMON'S FOR DECAY PROPERTIES
+      INTEGER NGMAX,NCMAX
+      PARAMETER (NGMAX=400,NCMAX=9000)
+      INTEGER EUNPA,EUIPC(NGMAX),EUIPDG(NGMAX),EUIDP(NGMAX),
+     &     EUCONV(NCMAX)
+      REAL EUPM(NGMAX),EUPLT(NGMAX)
+      COMMON/PCTABL/EUNPA,EUIPC,EUIPDG,EUPM,EUPLT,EUIDP
+      COMMON/CONVRT/EUCONV
+C---
+      IF(FSTEVT) THEN
+C---CHANGE HERE THE DEFAULT VALUES OF EURODEC COMMON'S
+C
+C---INITIALIZE EURODEC COMMON'S
+CC        CALL EUDCIN
+C---INITIALIZE EURODEC
+        CALL EUDINI
+      ENDIF
+C---CONSTRUCT THE HADRON FOR EURODEC FROM ID1,ID2
+      EUNP=1
+      IDHEP(IHEP)=IDPDG(IDHW(IHEP))
+      EUIP(1)=IPDGEU(IDHEP(IHEP))
+      EUAPM(1)=EUPM(EUCONV(IABS(EUIP(1))))
+      EUPCM(1,1)=PHEP(1,IHEP)
+      EUPCM(2,1)=PHEP(2,IHEP)
+      EUPCM(3,1)=PHEP(3,IHEP)
+      EUPCM(5,1)=SQRT(PHEP(1,IHEP)**2+PHEP(2,IHEP)**2+PHEP(3,IHEP)**2)
+      EUPCM(4,1)=SQRT(EUPCM(5,1)**2+EUAPM(1)**2)
+C NOT POLARIZED HADRONS
+      EUPHEL(1)=0
+C HADRONS START FROM PRIMARY VERTEX
+      EUPVTX(1,1)=0.
+      EUPVTX(2,1)=0.
+      EUPVTX(3,1)=0.
+C---LET EURODEC DO THE JOB
+      EUTEIL=0
+      CALL FRAGMT(1,1,0)
+C---UPDATE THE HERWIG TABLE : LOOP OVER N-EURODEC FINAL PARTICLES
+      DO 40 IIHEP=1,EUTEIL
+      NHEP=NHEP+1
+      ISTHEP(NHEP)=198
+      IF(EUDCAY(IIHEP).EQ.0) ISTHEP(NHEP)=1
+      IDHEP(NHEP)=IEUPDG(EUINDX(IIHEP))
+      CALL HWUIDT(1,IDHEP(NHEP),IDHW(NHEP),NAME)
+      IF(IIHEP.EQ.1) THEN
+        ISTHEP(IHEP)=199
+        JDAHEP(1,IHEP)=NHEP
+        JDAHEP(2,IHEP)=NHEP
+        ISTHEP(NHEP)=199
+        NHEPHF=NHEP
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=IHEP
+        JDAHEP(1,NHEP)=EUDCAY(IIHEP)/10000+NHEPHF-1
+        JDAHEP(2,NHEP)=MOD(EUDCAY(IIHEP),10000)+NHEPHF-1
+      ELSE
+        JMOHEP(1,NHEP)=MOD(EUORIG(IIHEP),10000)+NHEPHF-1
+        JMOHEP(2,NHEP)=NHEPHF
+        JDAHEP(1,NHEP)=EUDCAY(IIHEP)/10000+NHEPHF-1
+        JDAHEP(2,NHEP)=MOD(EUDCAY(IIHEP),10000)+NHEPHF-1
+      ENDIF
+      PHEP(1,NHEP)=EUPTEI(1,IIHEP)
+      PHEP(2,NHEP)=EUPTEI(2,IIHEP)
+      PHEP(3,NHEP)=EUPTEI(3,IIHEP)
+      PHEP(4,NHEP)=EUPTEI(4,IIHEP)
+      PHEP(5,NHEP)=EUPTEI(5,IIHEP)
+      VHEP(1,NHEP)=EUSECV(1,IIHEP)
+      VHEP(2,NHEP)=EUSECV(2,IIHEP)
+      VHEP(3,NHEP)=EUSECV(3,IIHEP)
+      VHEP(4,NHEP)=0.
+      IF (IIHEP.GT.NTMAX) CALL HWWARN('HWDEUR',99,*999)
+   40 CONTINUE
+  999 END
+CDECK  ID>, HWDFOR.
+*CMZ :-        -01/04/99  19.52.44  by  Mike Seymour
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDFOR(P0,P1,P2,P3,P4)
+C-----------------------------------------------------------------------
+C     Generates 4-body decay 0->1+2+3+4 using pure phase space
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION HWR,P0(5),P1(5),P2(5),P3(5),P4(5),B,C,AA,BB,
+     & CC,DD,EE,TT,S1,RS1,FF,S2,PP,QQ,RR,P1CM,P234(5),P2CM,P34(5),P3CM
+      DOUBLE PRECISION TWO
+      PARAMETER (TWO=2.D0)
+      EXTERNAL HWR
+      B=P0(5)-P1(5)
+      C=P2(5)+P3(5)+P4(5)
+      IF (B.LT.C) CALL HWWARN('HWDFOR',100,*999)
+      AA=(P0(5)+P1(5))**2
+      BB=B**2
+      CC=C**2
+      DD=(P3(5)+P4(5))**2
+      EE=(P3(5)-P4(5))**2
+      TT=(B-C)*P0(5)**7/16
+C Select squared masses S1 and S2 of 234 and 34 subsystems
+  10  S1=BB+HWR()*(CC-BB)
+      RS1=SQRT(S1)
+      FF=(RS1-P2(5))**2
+      S2=DD+HWR()*(FF-DD)
+      PP=(AA-S1)*(BB-S1)
+      QQ=((RS1+P2(5))**2-S2)*(FF-S2)/S1
+      RR=(S2-DD)*(S2-EE)/S2
+      IF (PP*QQ*RR*(FF-DD)**2.LT.TT*S1*S2*HWR()**2) GOTO 10
+C Do two body decays: 0-->1+234, 234-->2+34 and 34-->3+4
+      P1CM=SQRT(PP/4)/P0(5)
+      P234(5)=RS1
+      P2CM=SQRT(QQ/4)
+      P34(5)=SQRT(S2)
+      P3CM=SQRT(RR/4)
+      CALL HWDTWO(P0  ,P1,P234,P1CM,TWO,.TRUE.)
+      CALL HWDTWO(P234,P2,P34 ,P2CM,TWO,.TRUE.)
+      CALL HWDTWO(P34 ,P3,P4  ,P3CM,TWO,.TRUE.)
+  999 END
+CDECK  ID>, HWDFIV.
+*CMZ :-        -01/04/99  19.52.44  by  Mike Seymour
+*-- Author :    Ian Knowles
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDFIV(P0,P1,P2,P3,P4,P5)
+C-----------------------------------------------------------------------
+C     Generates 5-body decay 0->1+2+3+4+5 using pure phase space
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION HWR,P0(5),P1(5),P2(5),P3(5),P4(5),P5(5),B,C,
+     & AA,BB,CC,DD,EE,FF,TT,S1,RS1,GG,S2,RS2,HH,S3,PP,QQ,RR,SS,P1CM,
+     & P2345(5),P2CM,P345(5),P3CM,P45(5),P4CM
+      DOUBLE PRECISION TWO
+      PARAMETER (TWO=2.D0)
+      EXTERNAL HWR
+      B=P0(5)-P1(5)
+      C=P2(5)+P3(5)+P4(5)+P5(5)
+      IF (B.LT.C) CALL HWWARN('HWDFIV',100,*999)
+      AA=(P0(5)+P1(5))**2
+      BB=B**2
+      CC=C**2
+      DD=(P3(5)+P4(5)+P5(5))**2
+      EE=(P4(5)+P5(5))**2
+      FF=(P4(5)-P5(5))**2
+      TT=(B-C)*P0(5)**11/729
+C Select squared masses S1, S2 and S3 of 2345, 345 and 45 subsystems
+  10  S1=BB+HWR()*(CC-BB)
+      RS1=SQRT(S1)
+      GG=(RS1-P2(5))**2
+      S2=DD+HWR()*(GG-DD)
+      RS2=SQRT(S2)
+      HH=(RS2-P3(5))**2
+      S3=EE+HWR()*(HH-EE)
+      PP=(AA-S1)*(BB-S1)
+      QQ=((RS1+P2(5))**2-S2)*(GG-S2)/S1
+      RR=((RS2+P3(5))**2-S3)*(HH-S3)/S2
+      SS=(S3-EE)*(S3-FF)/S3
+      IF (PP*QQ*RR*SS*((GG-DD)*(HH-EE))**2.LT.TT*S1*S2*S3*HWR()**2)
+     & GOTO 10
+C Do two body decays: 0-->1+2345, 2345-->2+345, 345-->3+45 and 45-->4+5
+      P1CM=SQRT(PP/4)/P0(5)
+      P2345(5)=RS1
+      P2CM=SQRT(QQ/4)
+      P345(5)=RS2
+      P3CM=SQRT(RR/4)
+      P45(5)=SQRT(S3)
+      P4CM=SQRT(SS/4)
+      CALL HWDTWO(P0   ,P1,P2345,P1CM,TWO,.TRUE.)
+      CALL HWDTWO(P2345,P2,P345 ,P2CM,TWO,.TRUE.)
+      CALL HWDTWO(P345 ,P3,P45  ,P3CM,TWO,.TRUE.)
+      CALL HWDTWO(P45  ,P4,P5   ,P4CM,TWO,.TRUE.)
+  999 END
+CDECK  ID>, HWDHAD.
+*CMZ :-        -26/04/91  14.01.26  by  Federico Carminati
+*-- Author :    Ian Knowles, Bryan Webber & Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDHAD
+C-----------------------------------------------------------------------
+C     GENERATES DECAYS OF UNSTABLE HADRONS AND LEPTONS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWR,HWULDO,RN,BF,COSANG,RSUM,DIST(4),VERTX(4),
+     & PMIX,WTMX,WTMX2,XS,DOT1,DOT2,HWDPWT,HWDWWT,XXX,YYY
+      INTEGER IHEP,ID,MHEP,IDM,I,IDS,IM,MO,IPDG
+      LOGICAL STABLE
+      EXTERNAL HWR,HWDPWT,HWDWWT,HWULDO
+      IF (IERROR.NE.0) RETURN
+      DO 100 IHEP=1,NMXHEP
+      IF (IHEP.GT.NHEP) THEN
+        ISTAT=90
+        RETURN
+      ELSEIF (ISTHEP(IHEP).EQ.120 .AND.
+     &  JDAHEP(1,IHEP).EQ.IHEP.AND.JDAHEP(2,IHEP).EQ.IHEP) THEN
+C---COPY COLOUR SINGLET CMF
+        NHEP=NHEP+1
+        IF (NHEP.GT.NMXHEP) CALL HWWARN('HWDHAD',100,*999)
+        CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,NHEP))
+        CALL HWVEQU(4,VHEP(1,IHEP),VHEP(1,NHEP))
+        IDHW(NHEP)=IDHW(IHEP)
+        IDHEP(NHEP)=IDHEP(IHEP)
+        ISTHEP(NHEP)=190
+        JMOHEP(1,NHEP)=IHEP
+        JMOHEP(2,NHEP)=NHEP
+        JDAHEP(2,NHEP)=NHEP
+        JDAHEP(1,IHEP)=NHEP
+        JDAHEP(2,IHEP)=NHEP
+      ELSEIF (ISTHEP(IHEP).GE.190.AND.ISTHEP(IHEP).LE.193) THEN
+C---FIRST CHECK FOR STABILITY
+        ID=IDHW(IHEP)
+        IF (RSTAB(ID)) THEN
+          ISTHEP(IHEP)=1
+          JDAHEP(1,IHEP)=0
+          JDAHEP(2,IHEP)=0
+C---SPECIAL FOR GAUGE BOSON DECAY
+          IF (ID.GE.198.AND.ID.LE.200) CALL HWDBOS(IHEP)
+C---SPECIAL FOR HIGGS BOSON DECAY
+          IF (ID.EQ.201) CALL HWDHIG(ZERO)
+        ELSE
+C---UNSTABLE.
+C Calculate position of decay vertex
+          IF (DKLTM(ID).EQ.ZERO) THEN
+            CALL HWVEQU(4,VHEP(1,IHEP),VERTX)
+            MHEP=IHEP
+            IDM=ID
+          ELSE
+            CALL HWUDKL(ID,PHEP(1,IHEP),DIST)
+            CALL HWVSUM(4,VHEP(1,IHEP),DIST,VERTX)
+            IF (MAXDKL) THEN
+              CALL HWDXLM(VERTX,STABLE)
+              IF (STABLE) THEN
+                ISTHEP(IHEP)=1
+                JDAHEP(1,IHEP)=0
+                JDAHEP(2,IHEP)=0
+                GOTO 100
+              ENDIF
+            ENDIF
+            IF (MIXING.AND.(ID.EQ.221.OR.ID.EQ.223.OR.
+     &                      ID.EQ.245.OR.ID.EQ.247)) THEN
+C Select flavour of decaying b-meson allowing for flavour oscillation
+              IDS=MOD(ID,3)
+              XXX=XMRCT(IDS)*DIST(4)/PHEP(4,IHEP)
+              YYY=YMRCT(IDS)*DIST(4)/PHEP(4,IHEP)
+              IF (ABS(YYY).LT.10) THEN
+                PMIX=HALF*(ONE-COS(XXX)/COSH(YYY))
+              ELSE
+                PMIX=HALF
+              ENDIF
+              IF (HWR().LE.PMIX) THEN
+                IF (ID.LE.223) THEN
+                  IDM=ID+24
+                ELSE
+                  IDM=ID-24
+                ENDIF
+              ELSE
+                IDM=ID
+              ENDIF
+C Introduce a decaying neutral b-meson
+              IF (NHEP+1.GT.NMXHEP) CALL HWWARN('HWDHAD',101,*999)
+              MHEP=NHEP+1
+              ISTHEP(MHEP)=ISTHEP(IHEP)
+              ISTHEP(IHEP)=200
+              JDAHEP(1,IHEP)=MHEP
+              JDAHEP(2,IHEP)=MHEP
+              IDHW(MHEP)=IDM
+              IDHEP(MHEP)=IDPDG(IDM)
+              JMOHEP(1,MHEP)=IHEP
+              JMOHEP(2,MHEP)=JMOHEP(2,IHEP)
+              CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,MHEP))
+              CALL HWVEQU(4,VERTX,VHEP(1,MHEP))
+              NHEP=NHEP+1
+            ELSE
+              MHEP=IHEP
+              IDM=ID
+            ENDIF
+          ENDIF
+C Use CLEO/EURODEC packages for b-hadrons if requested
+          IF ((IDM.GE.221.AND.IDM.LE.231).OR.
+     &        (IDM.GE.245.AND.IDM.LE.254)) THEN
+            IF (BDECAY.EQ.'CLEO') THEN
+              CALL HWDCLE(MHEP)
+              GOTO 100
+            ELSEIF (BDECAY.EQ.'EURO') THEN
+              CALL HWDEUR(MHEP)
+              GOTO 100
+            ENDIF
+          ENDIF
+C Choose decay mode
+          ISTHEP(MHEP)=ISTHEP(MHEP)+5
+          RN=HWR()
+          BF=0.
+          IM=LSTRT(IDM)
+          DO 10 I=1,NMODES(IDM)
+          BF=BF+BRFRAC(IM)
+          IF (BF.GE.RN) GOTO 20
+  10      IM=LNEXT(IM)
+          CALL HWWARN('HWDHAD',50,*20)
+  20      IF ((IDKPRD(1,IM).GE.1.AND.IDKPRD(1,IM).LE.13).OR.
+     &        (IDKPRD(3,IM).GE.1.AND.IDKPRD(3,IM).LE.13)) THEN
+C Partonic decay of a heavy-(b,c)-hadron, store details
+            NQDK=NQDK+1
+            IF (NQDK.GT.NMXQDK) CALL HWWARN('HWDHAD',102,*999)
+            LOCQ(NQDK)=MHEP
+            IMQDK(NQDK)=IM
+            CALL HWVEQU(4,VERTX,VTXQDK(1,NQDK))
+            GOTO 100
+          ELSE
+C Exclusive decay, add decay products to event record
+            IF (NHEP+NPRODS(IM).GT.NMXHEP)
+     &        CALL HWWARN('HWDHAD',103,*999)
+            JDAHEP(1,MHEP)=NHEP+1
+            DO 30 I=1,NPRODS(IM)
+            NHEP=NHEP+1
+            IDHW(NHEP)=IDKPRD(I,IM)
+            IDHEP(NHEP)=IDPDG(IDKPRD(I,IM))
+            ISTHEP(NHEP)=193
+            JMOHEP(1,NHEP)=MHEP
+            JMOHEP(2,NHEP)=JMOHEP(2,MHEP)
+            PHEP(5,NHEP)=RMASS(IDKPRD(I,IM))
+  30        CALL HWVEQU(4,VERTX,VHEP(1,NHEP))
+            JDAHEP(2,MHEP)=NHEP
+          ENDIF
+C Next choose momenta:
+          IF (NPRODS(IM).EQ.1) THEN
+C 1-body decay: K0(BR) --> K0S,K0L
+            CALL HWVEQU(4,PHEP(1,MHEP),PHEP(1,NHEP))
+          ELSEIF (NPRODS(IM).EQ.2) THEN
+C 2-body decay
+C---SPECIAL TREATMENT OF POLARIZED MESONS
+            COSANG=TWO
+            IF (ID.EQ.IDHW(JMOHEP(1,MHEP))) THEN
+              MO=JMOHEP(1,MHEP)
+              RSUM=0
+              DO 40 I=1,3
+  40          RSUM=RSUM+RHOHEP(I,MO)
+              IF (RSUM.GT.ZERO) THEN
+                RSUM=RSUM*HWR()
+                IF (RSUM.LT.RHOHEP(1,MO)) THEN
+C---(1+COSANG)**2
+                  COSANG=MAX(HWR(),HWR(),HWR())*TWO-ONE
+                ELSEIF (RSUM.LT.RHOHEP(1,MO)+RHOHEP(2,MO)) THEN
+C---1-COSANG**2
+                  COSANG=2*COS((ACOS(HWR()*TWO-ONE)+PIFAC)/THREE)
+                ELSE
+C---(1-COSANG)**2
+                  COSANG=MIN(HWR(),HWR(),HWR())*TWO-ONE
+                ENDIF
+              ENDIF
+            ENDIF
+            CALL HWDTWO(PHEP(1,MHEP),PHEP(1,NHEP-1),
+     &                  PHEP(1,NHEP),CMMOM(IM),COSANG,.FALSE.)
+          ELSEIF (NPRODS(IM).EQ.3) THEN
+C 3-body decay
+            IF (NME(IM).EQ.100) THEN
+C  Use free massless (V-A)*(V-A) Matrix Element
+              CALL HWDTHR(PHEP(1,MHEP),PHEP(1,NHEP-1),PHEP(1,NHEP-2),
+     &                    PHEP(1,NHEP),HWDWWT)
+            ELSEIF (NME(IM).EQ.101) THEN
+C  Use bound massless (V-A)*(V-A) Matrix Element
+              WTMX=((PHEP(5,MHEP)-PHEP(5,NHEP))
+     &             *(PHEP(5,MHEP)+PHEP(5,NHEP))
+     &             +(PHEP(5,NHEP-1)-PHEP(5,NHEP-2))
+     &             *(PHEP(5,NHEP-1)+PHEP(5,NHEP-2)))/TWO
+              WTMX2=WTMX**2
+              IPDG=ABS(IDHEP(MHEP))
+              XS=ONE-MAX(RMASS(MOD(IPDG/1000,10)),
+     &                   RMASS(MOD(IPDG/100,10)),RMASS(MOD(IPDG/10,10)))
+     &              /(RMASS(MOD(IPDG/1000,10))+RMASS(MOD(IPDG/100,10))
+     &               +RMASS(MOD(IPDG/10,10)))
+  50          CALL HWDTHR(PHEP(1,MHEP),PHEP(1,NHEP-1),PHEP(1,NHEP-2),
+     &                    PHEP(1,NHEP),HWDWWT)
+              DOT1=HWULDO(PHEP(1,MHEP),PHEP(1,NHEP-1))
+              DOT2=HWULDO(PHEP(1,MHEP),PHEP(1,NHEP-2))
+              IF (DOT1*(WTMX-DOT1-XS*DOT2).LT.HWR()*WTMX2) GOTO 50
+            ELSE
+              CALL HWDTHR(PHEP(1,MHEP),PHEP(1,NHEP-2),PHEP(1,NHEP-1),
+     &                    PHEP(1,NHEP),HWDPWT)
+            ENDIF
+          ELSEIF (NPRODS(IM).EQ.4) THEN
+C 4-body decay
+            CALL HWDFOR(PHEP(1,MHEP  ),PHEP(1,NHEP-3),PHEP(1,NHEP-2),
+     &                  PHEP(1,NHEP-1),PHEP(1,NHEP))
+          ELSEIF (NPRODS(IM).EQ.5) THEN
+C 5-body decay
+            CALL HWDFIV(PHEP(1,MHEP  ),PHEP(1,NHEP-4),PHEP(1,NHEP-3),
+     &                  PHEP(1,NHEP-2),PHEP(1,NHEP-1),PHEP(1,NHEP))
+          ELSE
+            CALL HWWARN('HWDHAD',104,*999)
+          ENDIF
+        ENDIF
+      ENDIF
+  100 CONTINUE
+C---MAY HAVE OVERFLOWED /HEPEVT/
+      CALL HWWARN('HWDHAD',105,*999)
+  999 END
+CDECK  ID>, HWDHGC.
+*CMZ :-        -26/04/91  11.11.55  by  Bryan Webber
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDHGC(TAU,FNREAL,FNIMAG)
+C-----------------------------------------------------------------------
+C  CALCULATE THE COMPLEX FUNCTION F OF HHG eq 2.18
+C  FOR USE IN H-->GAMMGAMM DECAYS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION TAU,FNREAL,FNIMAG,FNLOG,FNSQR
+      IF (TAU.GT.ONE) THEN
+        FNREAL=(ASIN(1/SQRT(TAU)))**2
+        FNIMAG=0
+      ELSEIF (TAU.LT.ONE) THEN
+        FNSQR=SQRT(1-TAU)
+        FNLOG=LOG((1+FNSQR)/(1-FNSQR))
+        FNREAL=-0.25 * (FNLOG**2 - PIFAC**2)
+        FNIMAG= 0.5  * PIFAC*FNLOG
+      ELSE
+        FNREAL=0.25*PIFAC**2
+        FNIMAG=0
+      ENDIF
+      END
+CDECK  ID>, HWDHGF.
+*CMZ :-        -02/05/91  11.11.45  by  Federico Carminati
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      FUNCTION HWDHGF(X,Y)
+C-----------------------------------------------------------------------
+C  CALCULATE THE DOUBLE BREIT-WIGNER INTEGRAL
+C  X=(EMV/EMH)**2 , Y=EMV*GAMV/EMH**2
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWDHGF,X,Y,CHANGE,X1,X2,FAC1,FAC2,TH1,TH2,TH1HI,
+     & TH1LO,TH2HI,TH2LO,X2MAX,SQFAC
+      INTEGER NBIN,IBIN1,IBIN2
+C  CHANGE IS THE POINT WHERE DIRECT INTEGRATION BEGINS TO CONVERGE
+C  FASTER THAN STANDARD BREIT-WIGNER SUBSTITUTION
+      DATA CHANGE,NBIN/0.425,25/
+      HWDHGF=0
+      IF (Y.LT.ZERO) RETURN
+      IF (X.GT.CHANGE) THEN
+C---DIRECT INTEGRATION
+        FAC1=0.25 / NBIN
+        DO 200 IBIN1=1,NBIN
+          X1=(IBIN1-0.5) * FAC1
+          FAC2=( (1-SQRT(X1))**2-X1 ) / NBIN
+          DO 100 IBIN2=1,NBIN
+            X2=(IBIN2-0.5) * FAC2 + X1
+            SQFAC=1+X1**2+X2**2-2*(X1+X2+X1*X2)
+            IF (SQFAC.LT.ZERO) GOTO 100
+            HWDHGF=HWDHGF + 2.
+     &        * ((1-X1-X2)**2+8*X1*X2)
+     &        * SQRT(SQFAC)
+     &        / ((X1-X)**2+Y**2) *Y
+     &        / ((X2-X)**2+Y**2) *Y
+     &        * FAC1*FAC2
+ 100      CONTINUE
+ 200    CONTINUE
+      ELSE
+C---INTEGRATION USING TAN THETA SUBSTITUTIONS
+        TH1LO=ATAN((0-X)/Y)
+        TH1HI=ATAN((1-X)/Y)
+        FAC1=(TH1HI-TH1LO) / NBIN
+        DO 400 IBIN1=1,NBIN
+          TH1=(IBIN1-0.5) * FAC1 + TH1LO
+          X1=Y*TAN(TH1) + X
+          X2MAX=MIN(X1,(1-SQRT(X1))**2)
+          TH2LO=ATAN((0-X)/Y)
+          TH2HI=ATAN((X2MAX-X)/Y)
+          FAC2=(TH2HI-TH2LO) / NBIN
+          DO 300 IBIN2=1,NBIN
+            TH2=(IBIN2-0.5) * FAC2 + TH2LO
+            X2=Y*TAN(TH2) + X
+            SQFAC=1+X1**2+X2**2-2*(X1+X2+X1*X2)
+            IF (SQFAC.LT.ZERO) GOTO 300
+            HWDHGF=HWDHGF + 2.
+     &        * ((1-X1-X2)**2+8*X1*X2)
+     &        * SQRT(SQFAC)
+     &        * FAC1 * FAC2
+ 300      CONTINUE
+ 400    CONTINUE
+      ENDIF
+      HWDHGF=HWDHGF/(PIFAC*PIFAC)
+      END
+CDECK  ID>, HWDHIG.
+*CMZ :-        -24/04/92  14.23.44  by  Mike Seymour
+*-- Author :    Mike Seymour
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDHIG(GAMINP)
+C-----------------------------------------------------------------------
+C     HIGGS DECAY ROUTINE
+C     A) FOR GAMinp=0 FIND AND DECAY HIGGS
+C     B) FOR GAMinp>0 CALCULATE TOTAL HIGGS WIDTH
+C                     FOR EMH=GAMINP. STORE RESULT IN GAMINP.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWDHGF,HWR,HWRUNI,HWUSQR,HWUPCM,GAMINP,EMH,
+     & EMF,COLFAC,ENF,K1,K0,BET0,BET1,GAM0,GAM1,SCLOG,CFAC,XF,EM,GAMLIM,
+     & GAM,XW,EMW,XZ,EMZ,YW,YZ,EMI,TAUT,TAUW,WIDHIG,VECDEC,EMB,GAMB,
+     & TMIN,TMAX1,EM1,TMAX2,EM2,X1,X2,PROB,PCM,SUMR,SUMI,TAUTR,TAUTI,
+     & TAUWR,TAUWI,GFACTR
+      INTEGER HWRINT,IHIG,I,IFERM,NLOOK,I1,I2,IPART,IMODE,IDEC,MMAX
+      LOGICAL HWRLOG
+      EXTERNAL HWDHGF,HWR,HWRUNI,HWUSQR,HWUPCM,HWRINT,HWRLOG
+      SAVE GAM,EM,VECDEC
+      PARAMETER (NLOOK=100)
+      DIMENSION VECDEC(2,0:NLOOK)
+      EQUIVALENCE (EMW,RMASS(198)),(EMZ,RMASS(200))
+      DATA GAMLIM,GAM,EM/10D0,2*0D0/
+C---IF DECAY, FIND HIGGS (HWDHAD WILL HAVE GIVEN IT STATUS=1)
+      IF (GAMINP.EQ.ZERO) THEN
+        IHIG=0
+        DO 10 I=1,NHEP
+ 10       IF (IHIG.EQ.0.AND.IDHW(I).EQ.201.AND.ISTHEP(I).EQ.1) IHIG=I
+        IF (IHIG.EQ.0) CALL HWWARN('HWDHIG',101,*999)
+        EMH=PHEP(5,IHIG)
+        IF (EMH.LE.ZERO) CALL HWWARN('HWDHIG',102,*999)
+        EMSCA=EMH
+      ELSE
+        EMH=GAMINP
+        IF (EMH.LE.ZERO) THEN
+          GAMINP=0
+          RETURN
+        ENDIF
+      ENDIF
+C---CALCULATE BRANCHING FRACTIONS
+C---FERMIONS
+C---NLL CORRECTION TO QUARK DECAY RATE (HHG eq 2.6-9)
+      ENF=0
+      DO 1 I=1,6
+ 1      IF (2*RMASS(I).LT.EMH) ENF=ENF+1
+      K1=5/PIFAC**2
+      K0=3/(4*PIFAC**2)
+      BET0=(11*CAFAC-2*ENF)/3
+      BET1=(34*CAFAC**2-(10*CAFAC+6*CFFAC)*ENF)/3
+      GAM0=-8
+      GAM1=-404./3+40*ENF/9
+      SCLOG=LOG(EMH**2/QCDLAM**2)
+      CFAC=1 + ( K1/K0 - 2*GAM0 + GAM0*BET1/BET0**2*LOG(SCLOG)
+     &       +   (GAM0*BET1-GAM1*BET0)/BET0**2) / (BET0*SCLOG)
+      DO 100 IFERM=1,9
+        IF (IFERM.LE.6) THEN
+          EMF=RMASS(IFERM)
+          XF=(EMF/EMH)**2
+          COLFAC=FLOAT(NCOLO)
+          IF (EMF.GT.QCDLAM)
+     &      EMF=EMF*(LOG(EMH/QCDLAM)/LOG(EMF/QCDLAM))**(GAM0/(2*BET0))
+        ELSE
+          EMF=RMASS(107+IFERM*2)
+          XF=(EMF/EMH)**2
+          COLFAC=1
+          CFAC=1
+        ENDIF
+        IF (FOUR*XF.LT.ONE) THEN
+        GFACTR=ALPHEM/(8.*SWEIN*EMW**2)
+          BRHIG(IFERM)=COLFAC*GFACTR*EMH*EMF**2 * (1-4*XF)**1.5 * CFAC
+        ELSE
+          BRHIG(IFERM)=0
+        ENDIF
+ 100  CONTINUE
+C---W*W*/Z*Z*
+      IF (ABS(EM-EMH).GE.GAMLIM*GAM) THEN
+C---OFF EDGE OF LOOK-UP TABLE
+        XW=(EMW/EMH)**2
+        XZ=(EMZ/EMH)**2
+        YW=EMW*GAMW/EMH**2
+        YZ=EMZ*GAMZ/EMH**2
+        BRHIG(10)=.50*GFACTR * EMH**3 * HWDHGF(XW,YW)
+        BRHIG(11)=.25*GFACTR * EMH**3 * HWDHGF(XZ,YZ)
+      ELSE
+C---LOOK IT UP
+        EMI=((EMH-EM)/(GAM*GAMLIM)+1)*NLOOK/2.0
+        I1=INT(EMI)
+        I2=INT(EMI+1)
+        BRHIG(10)=.50*GFACTR * EMH**3 * ( VECDEC(1,I1)*(I2-EMI) +
+     &                                    VECDEC(1,I2)*(EMI-I1) )
+        BRHIG(11)=.25*GFACTR * EMH**3 * ( VECDEC(2,I1)*(I2-EMI) +
+     &                                    VECDEC(2,I2)*(EMI-I1) )
+      ENDIF
+C---GAMMAGAMMA
+      TAUT=(2*RMASS(6)/EMH)**2
+      TAUW=(2*EMW/EMH)**2
+      CALL HWDHGC(TAUT,TAUTR,TAUTI)
+      CALL HWDHGC(TAUW,TAUWR,TAUWI)
+      SUMR=4./3*(  - 2*TAUT*( 1 + (1-TAUT)*TAUTR ) ) * ENHANC(6)
+     &         +(2 + 3*TAUW*( 1 + (2-TAUW)*TAUWR ) ) * ENHANC(10)
+      SUMI=4./3*(  - 2*TAUT*(     (1-TAUT)*TAUTI ) ) * ENHANC(6)
+     &         +(    3*TAUW*(     (2-TAUW)*TAUWI ) ) * ENHANC(10)
+      BRHIG(12)=GFACTR*.03125*(ALPHEM/PIFAC)**2
+     &         *EMH**3 * (SUMR**2 + SUMI**2)
+      WIDHIG=0
+      DO 200 IPART=1, 12
+        IF (IPART.LT.12) BRHIG(IPART)=BRHIG(IPART)*ENHANC(IPART)**2
+ 200    WIDHIG=WIDHIG+BRHIG(IPART)
+      IF (WIDHIG.EQ.ZERO) CALL HWWARN('HWDHIG',103,*999)
+      DO 300 IPART=1, 12
+ 300    BRHIG(IPART)=BRHIG(IPART)/WIDHIG
+      IF (EM.NE.RMASS(201)) THEN
+C---SET UP W*W*/Z*Z* LOOKUP TABLES
+        EM=EMH
+        GAM=WIDHIG
+        GAMLIM=MAX(GAMLIM,GAMMAX)
+        DO 400 I=0,NLOOK
+          EMH=(I*2.0/NLOOK-1)*GAM*GAMLIM+EM
+          XW=(EMW/EMH)**2
+          XZ=(EMZ/EMH)**2
+          YW=EMW*GAMW/EMH**2
+          YZ=EMZ*GAMZ/EMH**2
+          VECDEC(1,I)=HWDHGF(XW,YW)
+          VECDEC(2,I)=HWDHGF(XZ,YZ)
+ 400    CONTINUE
+        EMH=EM
+      ENDIF
+      IF (GAMINP.GT.ZERO) THEN
+        GAMINP=WIDHIG
+        RETURN
+      ENDIF
+C---SEE IF USER SPECIFIED A DECAY MODE
+      IMODE=MOD(IPROC,100)
+C---IF NOT, CHOOSE ONE
+      IF (IMODE.LT.1.OR.IMODE.GT.12) THEN
+        MMAX=12
+        IF (IMODE.LT.1) MMAX=6
+ 500    IMODE=HWRINT(1,MMAX)
+        IF (BRHIG(IMODE).LT.HWR()) GOTO 500
+      ENDIF
+C---SEE IF SPECIFIED DECAY IS POSSIBLE
+      IF (BRHIG(IMODE).EQ.ZERO) CALL HWWARN('HWDHIG',104,*999)
+      IF (IMODE.LE.6) THEN
+        IDEC=IMODE
+      ELSEIF (IMODE.LE.9) THEN
+        IDEC=107+IMODE*2
+      ELSEIF (IMODE.EQ.10) THEN
+        IDEC=198
+      ELSEIF (IMODE.EQ.11) THEN
+        IDEC=200
+      ELSEIF (IMODE.EQ.12) THEN
+        IDEC=59
+      ENDIF
+C---STATUS, IDs AND POINTERS
+      ISTHEP(IHIG)=195
+      DO 600 I=1,2
+        ISTHEP(NHEP+I)=193
+        IDHW(NHEP+I)=IDEC
+        IDHEP(NHEP+I)=IDPDG(IDEC)
+        JDAHEP(I,IHIG)=NHEP+I
+        JMOHEP(1,NHEP+I)=IHIG
+        JMOHEP(2,NHEP+I)=NHEP+(3-I)
+        JDAHEP(2,NHEP+I)=NHEP+(3-I)
+        PHEP(5,NHEP+I)=RMASS(IDEC)
+        IDEC=IDEC+6
+        IF (IDEC.EQ.204) IDEC=199
+        IF (IDEC.EQ.206) IDEC=200
+        IF (IDEC.EQ. 65) IDEC= 59
+ 600  CONTINUE
+C---ALLOW W/Z TO BE OFF-SHELL
+      IF (IMODE.EQ.10.OR.IMODE.EQ.11) THEN
+        IF (IMODE.EQ.10) THEN
+          EMB=EMW
+          GAMB=GAMW
+        ELSE
+          EMB=EMZ
+          GAMB=GAMZ
+        ENDIF
+C---STANDARD MASS DISTRIBUTION
+ 700    TMIN=ATAN(-EMB/GAMB)
+        TMAX1=ATAN((EMH**2/EMB-EMB)/GAMB)
+        EM1=HWUSQR(EMB*(GAMB*TAN(HWRUNI(0,TMIN,TMAX1))+EMB))
+        TMAX2=ATAN(((EMH-EM1)**2/EMB-EMB)/GAMB)
+        EM2=HWUSQR(EMB*(GAMB*TAN(HWRUNI(0,TMIN,TMAX2))+EMB))
+        X1=(EM1/EMH)**2
+        X2=(EM2/EMH)**2
+C---CORRECT MASS DISTRIBUTION
+        PROB=HWUSQR(1+X1**2+X2**2-2*X1-2*X2-2*X1*X2)
+     &        * ((X1+X2-1)**2 + 8*X1*X2)
+        IF (.NOT.HWRLOG(PROB)) GOTO 700
+C---CALCULATE SPIN DENSITY MATRIX
+        RHOHEP(1,NHEP+1)=4*X1*X2      / (8*X1*X2 + (X1+X2-1)**2)
+        RHOHEP(2,NHEP+1)=(X1+X2-1)**2 / (8*X1*X2 + (X1+X2-1)**2)
+        RHOHEP(3,NHEP+1)=RHOHEP(1,NHEP+1)
+C---SYMMETRIZE DISTRIBUTIONS IN PARTICLES 1,2
+        IF (HWRLOG(HALF)) THEN
+          PHEP(5,NHEP+1)=EM1
+          PHEP(5,NHEP+2)=EM2
+        ELSE
+          PHEP(5,NHEP+1)=EM2
+          PHEP(5,NHEP+2)=EM1
+        ENDIF
+      ENDIF
+C---DO DECAY
+      PCM=HWUPCM(EMH,PHEP(5,NHEP+1),PHEP(5,NHEP+2))
+      IF (PCM.LT.ZERO) CALL HWWARN('HWDHIG',105,*999)
+      CALL HWDTWO(PHEP(1,IHIG),PHEP(1,NHEP+1),PHEP(1,NHEP+2),
+     &            PCM,TWO,.TRUE.)
+      NHEP=NHEP+2
+C---IF QUARK DECAY, HADRONIZE
+      IF (IMODE.LE.6) THEN
+        ISTHEP(NHEP-1)=113
+        ISTHEP(NHEP)=114
+        CALL HWBGEN
+        CALL HWDHOB
+        CALL HWCFOR
+        CALL HWCDEC
+      ENDIF
+  999 END
+CDECK  ID>, HWDHOB.
+*CMZ :-        -20/10/99  09:46:43  by  Peter Richardson
+*-- Author :    Ian Knowles & Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDHOB
+C-----------------------------------------------------------------------
+C   Performs decays of heavy objects (heavy quarks & SUSY particles)
+C   MODIFIED TO INCLUDE R-PARITY VIOLATING SUSY PR 9/4/99
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWUMBW,HWUPCM,HWR,SDKM,RN,BF,PCM,
+     & EMMX,EMWSQ,GMWSQ,EMLIM,PW(5),EMTST,HWDPWT,HWDWWT,HWULDO,PDW(5,3)
+      INTEGER IST(3),IHEP,IS,ID,IM,I,JHEP,KHEP,LHEP,MHEP,NPR,ISM,JCM,
+     & MTRY,NTRY,IDM,IDM2,THEP,CLSAVE(2),WHEP,RHEP
+      LOGICAL FOUND
+      EXTERNAL HWR,HWDPWT,HWDWWT
+      DATA IST/113,114,114/
+      IF (IERROR.NE.0) RETURN
+  10  FOUND=.FALSE.
+      CLSAVE(1) = 0
+      CLSAVE(2) = 0
+      DO 60 IHEP=1,NMXHEP
+      IS=ISTHEP(IHEP)
+      ID=IDHW(IHEP)
+      IF (.NOT.RSTAB(ID).AND.(ID.EQ.6.OR.ID.EQ.12.OR.
+     & (ID.GE.203.AND.ID.LE.218).OR.ABS(IDPDG(ID)).GT.1000000).AND.
+     & (IS.EQ.190.OR.(IS.GE.147.AND.IS.LE.151))) THEN
+        FOUND=.TRUE.
+        IF(.NOT.RPARTY) THEN
+          NHEP = NHEP+1
+          ISTHEP(NHEP) = 3
+          IDHW(NHEP) = 20
+          IDHEP(NHEP) = 0
+          CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,NHEP))
+          CALL HWVEQU(4,VHEP(1,IHEP),VHEP(1,NHEP))
+          JMOHEP(1,NHEP)=JMOHEP(1,IHEP)
+          JMOHEP(2,NHEP)=JMOHEP(2,IHEP)
+          JDAHEP(1,NHEP)=JDAHEP(1,IHEP)
+          JDAHEP(2,NHEP)=JDAHEP(2,IHEP)
+        ENDIF
+C Make a copy of decaying object
+        NHEP=NHEP+1
+        ISTHEP(NHEP)=155
+        IDHW(NHEP)=IDHW(IHEP)
+        IDHEP(NHEP)=IDHEP(IHEP)
+        CALL HWVEQU(5,PHEP(1,IHEP),PHEP(1,NHEP))
+        CALL HWVEQU(4,VHEP(1,IHEP),VHEP(1,NHEP))
+        JMOHEP(1,NHEP)=JMOHEP(1,IHEP)
+        JMOHEP(2,NHEP)=JMOHEP(2,IHEP)
+        MTRY=0
+ 15     MTRY=MTRY+1
+C Select decay mode
+        RN=HWR()
+        BF=0.
+        IM=LSTRT(ID)
+        DO 20 I=1,NMODES(ID)
+        BF=BF+BRFRAC(IM)
+        IF (BF.GE.RN) GOTO 30
+  20    IM=LNEXT(IM)
+        CALL HWWARN('HWDHOB',50,*30)
+  30    IF (NHEP+5.GT.NMXHEP) CALL HWWARN('HWDHOB',100,*999)
+        NPR=NPRODS(IM)
+        JDAHEP(1,NHEP)=NHEP+1
+        JDAHEP(2,NHEP)=NHEP+NPR
+C Reset colour pointers (if set)
+        JHEP=JMOHEP(2,IHEP)
+        IF (JHEP.GT.0) THEN
+          IF (JDAHEP(2,JHEP).EQ.IHEP) JDAHEP(2,JHEP)=NHEP
+          IF(.NOT.RPARTY.AND.ISTHEP(JHEP).EQ.155
+     &    .AND.ABS(IDHEP(JHEP)).GT.1000000
+     &    .AND.JDAHEP(2,JHEP-1).EQ.IHEP) JDAHEP(2,JHEP-1) = NHEP
+        ENDIF
+        JHEP=JDAHEP(2,IHEP)
+        IF (JHEP.GT.0) THEN
+          IF (JMOHEP(2,JHEP).EQ.IHEP) JMOHEP(2,JHEP)=NHEP
+          IF(.NOT.RPARTY.AND.ISTHEP(JHEP).EQ.155
+     &    .AND.ABS(IDHEP(JHEP)).GT.1000000
+     &    .AND.JMOHEP(2,JHEP-1).EQ.IHEP) JMOHEP(2,JHEP-1) = NHEP
+        ENDIF
+C--Reset colour pointers if baryon number violated
+        IF(.NOT.RPARTY) THEN
+          DO JHEP=1,NHEP
+            IF(ISTHEP(JHEP).EQ.155
+     &         .AND.ABS(IDHEP(JHEP)).GT.1000000.AND.
+     &         JDAHEP(2,JHEP-1).EQ.IHEP) JDAHEP(2,JHEP-1)= NHEP
+            IF(JDAHEP(2,JHEP).EQ.IHEP) JDAHEP(2,JHEP)=NHEP
+            IF(JMOHEP(2,JHEP).EQ.IHEP) JMOHEP(2,JHEP)=NHEP
+          ENDDO
+          IF(HRDCOL(1,1).EQ.IHEP) HRDCOL(1,1)=NHEP
+        ENDIF
+C Relabel original track
+        ISTHEP(IHEP)=3
+        JMOHEP(2,IHEP)=JMOHEP(1,IHEP)
+        JDAHEP(1,IHEP)=NHEP
+        JDAHEP(2,IHEP)=NHEP
+C Label decay products and choose masses
+        LHEP=NHEP
+        MHEP=LHEP+1
+        NTRY=0
+ 35     NTRY=NTRY+1
+        SDKM=PHEP(5,NHEP)
+        DO 40 I=1,NPR
+        NHEP=NHEP+1
+        IDHW(NHEP)=IDKPRD(I,IM)
+        IDHEP(NHEP)=IDPDG(IDKPRD(I,IM))
+        ISTHEP(NHEP)=IST(I)
+        JMOHEP(1,NHEP)=LHEP
+        JDAHEP(1,NHEP)=0
+        PHEP(5,NHEP)=HWUMBW(IDKPRD(I,IM))
+ 40     SDKM=SDKM-PHEP(5,NHEP)
+        IF (SDKM.LT.ZERO) THEN
+          NHEP=NHEP-NPR
+          IF (NTRY.LE.NETRY) GO TO 35
+          CALL HWWARN('HWDHOB',1,*45)
+ 45       IF (MTRY.LE.NETRY) GO TO 15
+          CALL HWWARN('HWDHOB',101,*999)
+        ENDIF
+C Assign production vertices to decay products
+        CALL HWUDKL(ID,PHEP(1,IHEP),VHEP(1,MHEP))
+        CALL HWVSUM(4,VHEP(1,IHEP),VHEP(1,MHEP),VHEP(1,MHEP))
+        CALL HWVEQU(4,VHEP(1,MHEP),VHEP(1,NHEP))
+        IF (NPR.EQ.2) THEN
+C Two body decay: LHEP -> MHEP + NHEP
+          PCM=HWUPCM(PHEP(5,IHEP),PHEP(5,MHEP),PHEP(5,NHEP))
+          CALL HWDTWO(PHEP(1,IHEP),PHEP(1,MHEP),
+     &                PHEP(1,NHEP),PCM,TWO,.FALSE.)
+        ELSEIF (NPR.EQ.3) THEN
+C Three body decay: LHEP -> KHEP + MHEP + NHEP
+          KHEP=MHEP
+          MHEP=MHEP+1
+C Provisional colour self-connection of KHEP
+          JMOHEP(2,KHEP)=KHEP
+          JDAHEP(2,KHEP)=KHEP
+          IF (NME(IM).EQ.100) THEN
+C Generate decay momenta using full (V-A)*(V-A) matrix element
+            EMMX=PHEP(5,IHEP)-PHEP(5,NHEP)
+            EMWSQ=RMASS(198)**2
+            GMWSQ=(RMASS(198)*GAMW)**2
+            EMLIM=GMWSQ
+            IF (EMMX.LT.RMASS(198)) EMLIM=EMLIM+(EMWSQ-EMMX**2)**2
+  50        CALL HWDTHR(PHEP(1,IHEP),PHEP(1,MHEP),
+     &                  PHEP(1,KHEP),PHEP(1,NHEP),HWDWWT)
+            CALL HWVSUM(4,PHEP(1,KHEP),PHEP(1,MHEP),PW)
+            PW(5)=HWULDO(PW,PW)
+            EMTST=(EMWSQ-PW(5))**2
+            IF ((EMTST+GMWSQ)*HWR().GT.EMLIM) GOTO 50
+            PW(5)=SQRT(PW(5))
+C Assign production vertices to 1 and 2
+            CALL HWUDKL(198,PW,VHEP(1,KHEP))
+            CALL HWVSUM(4,VHEP(1,NHEP),VHEP(1,KHEP),VHEP(1,KHEP))
+          ELSEIF(NME(IM).EQ.300) THEN
+C Generate momenta using 3-body RPV matrix element
+            CALL HWDRME(LHEP,KHEP)
+          ELSE
+C Three body phase space decay
+            CALL HWDTHR(PHEP(1,IHEP),PHEP(1,MHEP),
+     &                  PHEP(1,KHEP),PHEP(1,NHEP),HWDPWT)
+          ENDIF
+          CALL HWVEQU(4,VHEP(1,KHEP),VHEP(1,MHEP))
+        ELSEIF(NPR.EQ.4) THEN
+C Four body decay: LHEP -> KHEP + RHEP + MHEP + NHEP
+          KHEP = MHEP
+          RHEP = MHEP+1
+          MHEP = MHEP+2
+C Provisional colour connections of KHEP and RHEP
+          JMOHEP(2,KHEP)=RHEP
+          JDAHEP(2,KHEP)=RHEP
+          JMOHEP(2,RHEP)=KHEP
+          JDAHEP(2,RHEP)=KHEP
+C Four body phase space decay
+          CALL HWDFOR(PHEP(1,IHEP),PHEP(1,KHEP),PHEP(1,RHEP),
+     &                  PHEP(1,MHEP),PHEP(1,NHEP))
+          CALL HWVEQU(4,VHEP(1,KHEP),VHEP(1,RHEP))
+          CALL HWVEQU(4,VHEP(1,KHEP),VHEP(1,MHEP))
+        ELSE
+          CALL HWWARN('HWDHOB',102,*999)
+        ENDIF
+C Colour connections
+        IF (ID.EQ.6.OR.ID.EQ.12.OR.(ID.GE.209.AND.ID.LE.212)
+     &                         .OR.(ID.GE.215.AND.ID.LE.218)) THEN
+          IF (NPR.EQ.3.AND.NME(IM).EQ.100) THEN
+C usual heavy quark decay
+            JMOHEP(2,KHEP)=MHEP
+            JDAHEP(2,KHEP)=MHEP
+            JMOHEP(2,MHEP)=KHEP
+            JDAHEP(2,MHEP)=KHEP
+            JMOHEP(2,NHEP)=LHEP
+            JDAHEP(2,NHEP)=LHEP
+          ELSEIF (ABS(IDHEP(MHEP)).EQ.37) THEN
+C heavy quark to charged Higgs
+            JMOHEP(2,MHEP)=MHEP
+            JDAHEP(2,MHEP)=MHEP
+            JMOHEP(2,NHEP)=LHEP
+            JDAHEP(2,NHEP)=LHEP
+          ELSEIF (ABS(IDHEP(NHEP)).EQ.37) THEN
+            JMOHEP(2,MHEP)=LHEP
+            JDAHEP(2,MHEP)=LHEP
+            JMOHEP(2,NHEP)=NHEP
+            JDAHEP(2,NHEP)=NHEP
+          ELSE
+            CALL HWWARN('HWDHOB',103,*999)
+          ENDIF
+        ELSE
+          IF(.NOT.RPARTY.AND.
+     &       ((NPR.EQ.2.AND.ID.GE.401.AND.ID.LT.448.AND.
+     &           IDHW(MHEP).LE.132.AND.IDHW(NHEP).LE.132)
+     &       .OR.(NPR.EQ.3.AND.ID.GE.449.AND.ID.LE.457.AND.
+     &           IDHW(MHEP).LE.132.AND.IDHW(NHEP).LE.132.AND.
+     &           IDHW(MHEP-1).LE.132))) THEN
+C R-parity violating SUSY decays
+            IF(NPR.EQ.2) THEN
+C--Rparity slepton colour connections
+              IF(ID.GE.425.AND.ID.LE.448) THEN
+                IF(IDHW(MHEP).GT.12) THEN
+                  JMOHEP(2,MHEP) = MHEP
+                  JDAHEP(2,MHEP) = MHEP
+                  JMOHEP(2,NHEP) = NHEP
+                  JDAHEP(2,NHEP) = NHEP
+                ELSE
+                  JMOHEP(2,MHEP) = NHEP
+                  JDAHEP(2,MHEP) = NHEP
+                  JMOHEP(2,NHEP) = MHEP
+                  JDAHEP(2,NHEP) = MHEP
+                ENDIF
+C--Rparity squark colour connections
+              ELSE
+                IF(IDHEP(LHEP).GT.0) THEN
+C--LQD decay colour connections
+                  IF(IDHW(MHEP).GT.12) THEN
+                    JMOHEP(2,MHEP) = MHEP
+                    JDAHEP(2,MHEP) = MHEP
+                    JMOHEP(2,NHEP) = LHEP
+                    JDAHEP(2,NHEP) = LHEP
+                  ELSE
+C--UDD decay colour connections
+                    HVFCEN = .TRUE.
+                    CALL HWDRCL(LHEP,MHEP,CLSAVE)
+                  ENDIF
+                ELSE
+C--Antisquark connections
+                  IF(IDHW(MHEP).GT.12) THEN
+                    JMOHEP(2,MHEP) = MHEP
+                    JDAHEP(2,MHEP) = MHEP
+                    JMOHEP(2,NHEP) = LHEP
+                   JDAHEP(2,NHEP) = LHEP
+                  ELSE
+                    HVFCEN = .TRUE.
+                   CALL HWDRCL(LHEP,MHEP,CLSAVE)
+                  ENDIF
+                ENDIF
+              ENDIF
+            ELSE
+              IF(ID.GE.450.AND.ID.LE.457) THEN
+C--Rparity Neutralino/Chargino colour connection
+                IF(IDHW(MHEP-1).LE.12.AND.IDHW(MHEP).LE.12.
+     &                 AND.IDHW(NHEP).LE.12) THEN
+                  HVFCEN = .TRUE.
+                  CALL HWDRCL(LHEP,MHEP,CLSAVE)
+                ELSE
+                  JMOHEP(2,MHEP) = NHEP
+                  JDAHEP(2,MHEP) = NHEP
+                  JMOHEP(2,NHEP) = MHEP
+                  JDAHEP(2,NHEP) = MHEP
+                ENDIF
+C--Rparity gluino colour connections
+              ELSEIF(ID.EQ.449) THEN
+                IF(IDHW(MHEP-1).LE.12.AND.IDHW(MHEP).LE.12.
+     &                 AND.IDHW(NHEP).LE.12) THEN
+                  HVFCEN = .TRUE.
+                  CALL HWDRCL(LHEP,MHEP,CLSAVE)
+C--Now the lepton number violating decay
+                ELSE
+                  IF(IDHW(MHEP).LE.6) THEN
+                    JMOHEP(2,MHEP) = LHEP
+                    JDAHEP(2,MHEP) = NHEP
+                    JMOHEP(2,NHEP) = MHEP
+                    JDAHEP(2,NHEP) = LHEP
+                  ELSE
+                    JMOHEP(2,MHEP) = NHEP
+                    JDAHEP(2,MHEP) = LHEP
+                    JMOHEP(2,NHEP) = LHEP
+                    JDAHEP(2,NHEP) = MHEP
+                  ENDIF
+                ENDIF
+              ELSE
+                CALL HWWARN('HWDHOB',104,*999)
+              ENDIF
+            ENDIF
+          ELSE
+C Normal SUSY decays
+            IF (ID.LE.448.AND.ID.GT.207) THEN
+C Squark (or slepton)
+              IF (IDHW(MHEP).EQ.449) THEN
+                IF (IDHEP(LHEP).GT.0) THEN
+                  JMOHEP(2,MHEP)=LHEP
+                  JDAHEP(2,MHEP)=NHEP
+                  JMOHEP(2,NHEP)=MHEP
+                  JDAHEP(2,NHEP)=LHEP
+                ELSE
+                  JMOHEP(2,MHEP)=NHEP
+                  JDAHEP(2,MHEP)=LHEP
+                  JMOHEP(2,NHEP)=LHEP
+                  JDAHEP(2,NHEP)=MHEP
+                ENDIF
+              ELSE
+                IF(NPR.EQ.3.AND.IDHW(MHEP).LE.12) THEN
+                  JMOHEP(2,MHEP)=NHEP
+                  JDAHEP(2,MHEP)=NHEP
+                  JMOHEP(2,NHEP)=MHEP
+                  JDAHEP(2,NHEP)=MHEP
+                ELSE
+                  JMOHEP(2,MHEP)=MHEP
+                  JDAHEP(2,MHEP)=MHEP
+                  JMOHEP(2,NHEP)=LHEP
+                  JDAHEP(2,NHEP)=LHEP
+                ENDIF
+              ENDIF
+            ELSEIF (ID.EQ.449) THEN
+C Gluino
+              IF (IDHW(NHEP).EQ.13) THEN
+                JMOHEP(2,MHEP)=MHEP
+                JDAHEP(2,MHEP)=MHEP
+                JMOHEP(2,NHEP)=LHEP
+                JDAHEP(2,NHEP)=LHEP
+              ELSEIF (IDHEP(MHEP).GT.0) THEN
+                JMOHEP(2,MHEP)=LHEP
+                JDAHEP(2,MHEP)=NHEP
+                JMOHEP(2,NHEP)=MHEP
+                JDAHEP(2,NHEP)=LHEP
+              ELSE
+                JMOHEP(2,MHEP)=NHEP
+                JDAHEP(2,MHEP)=LHEP
+                JMOHEP(2,NHEP)=LHEP
+                JDAHEP(2,NHEP)=MHEP
+              ENDIF
+            ELSE
+C Gaugino or Higgs
+              JMOHEP(2,MHEP)=NHEP
+              JDAHEP(2,MHEP)=NHEP
+              JMOHEP(2,NHEP)=MHEP
+              JDAHEP(2,NHEP)=MHEP
+            ENDIF
+          ENDIF
+        ENDIF
+C---SPECIAL CASE FOR THREE-BODY TOP DECAYS:
+C   RELABEL THEM AS TWO TWO-BODY DECAYS FOR PARTON SHOWERING
+        IF ((ID.EQ.6.OR.ID.EQ.12).AND.NPR.EQ.3.AND.NME(IM).EQ.100) THEN
+C---STORE W DECAY PRODUCTS
+          CALL HWVEQU(10,PHEP(1,KHEP),PDW)
+C---BOOST THEM INTO W REST FRAME
+          CALL HWULOF(PW,PDW(1,1),PDW(1,3))
+C---REPLACE THEM BY W
+          CALL HWVEQU(5,PW,PHEP(1,KHEP))
+          WHEP=KHEP
+          IDHW(KHEP)=198
+          IF (ID.EQ.12) IDHW(KHEP)=199
+          IDHEP(KHEP)=IDPDG(IDHW(KHEP))
+          JMOHEP(2,KHEP)=KHEP
+          JDAHEP(2,KHEP)=KHEP
+          CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,KHEP))
+C---AND MOVE B UP
+          CALL HWVEQU(5,PHEP(1,NHEP),PHEP(1,MHEP))
+          IDHW(MHEP)=IDHW(NHEP)
+          IDHEP(MHEP)=IDHEP(NHEP)
+          JDAHEP(2,LHEP)=MHEP
+          JMOHEP(2,MHEP)=JMOHEP(2,NHEP)
+          JDAHEP(2,MHEP)=JDAHEP(2,NHEP)
+          CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,MHEP))
+          NHEP=MHEP
+C---DO PARTON SHOWER
+          EMSCA=PHEP(5,IHEP)
+          CALL HWBGEN
+          IF (IERROR.NE.0) RETURN
+C---FIND BOOSTED W MOMENTUM
+          NTRY=0
+ 41       NTRY=NTRY+1
+          IF (NTRY.GT.NHEP.OR.WHEP.LE.0.OR.WHEP.GT.NHEP)
+     $         CALL HWWARN('HWDHOB',101,*999)
+          WHEP=JDAHEP(1,WHEP)
+          IF (ISTHEP(WHEP).NE.190) GOTO 41
+C---AND HENCE ITS CHILDRENS MOMENTA
+          CALL HWULOB(PHEP(1,WHEP),PDW(1,3),PHEP(1,NHEP+1))
+          CALL HWVDIF(4,PHEP(1,WHEP),PHEP(1,NHEP+1),PHEP(1,NHEP+2))
+          PHEP(5,NHEP+2)=PDW(5,2)
+C---LABEL THEM
+          ISTHEP(WHEP)=195
+          DO 51 I=1,2
+            IDHW(NHEP+I)=IDKPRD(I,IM)
+            IDHEP(NHEP+I)=IDPDG(IDHW(NHEP+I))
+            ISTHEP(NHEP+I)=112+I
+            JDAHEP(I,WHEP)=NHEP+I
+            JMOHEP(1,NHEP+I)=WHEP
+            JMOHEP(2,NHEP+I)=NHEP+3-I
+            JDAHEP(2,NHEP+I)=NHEP+3-I
+ 51       CONTINUE
+          NHEP=NHEP+2
+C---ASSIGN PRODUCTION VERTICES TO 1 AND 2
+          CALL HWUDKL(198,PW,VHEP(1,NHEP))
+          CALL HWVSUM(4,VHEP(1,WHEP),VHEP(1,NHEP),VHEP(1,NHEP))
+          CALL HWVEQU(4,VHEP(1,NHEP),VHEP(1,NHEP-1))
+C---DO PARTON SHOWERS
+          EMSCA=PW(5)
+          CALL HWBGEN
+          IF (IERROR.NE.0) RETURN
+        ELSE
+C Do parton showers
+          EMSCA=PHEP(5,IHEP)
+          CALL HWBGEN
+          IF (IERROR.NE.0) RETURN
+        ENDIF
+      ENDIF
+C--New to correct colour connections in Rslash
+      IF(CLSAVE(1).NE.0) THEN
+        THEP = MHEP+1
+        ID   = IDHW(CLSAVE(1))
+        IDM  = IDHW(JMOHEP(1,CLSAVE(1)))
+        IDM2 = IDHW(LHEP)
+        IF(IDM.EQ.15) ID=IDHW(JMOHEP(1,JMOHEP(1,CLSAVE(1))))
+        IF((ID.LE.6.AND.((IDM.GE.419.AND.IDM.LE.424).OR.IDM.EQ.411.OR.
+     &      IDM.EQ.412).
+     &     AND.((IDM2.GE.413.AND.IDM2.LE.418)
+     &     .OR.IDM2.EQ.449).OR.IDM2.EQ.405.OR.IDM2.EQ.406)
+     &     .OR.(ID.LE.6.AND.IDM.EQ.449.AND.
+     &    (((IDM2.GE.413.AND.IDM2.LE.418).OR.IDM2.EQ.405.OR.IDM2.EQ.406)
+     &     .OR.IDM2.EQ.449)).OR.
+     &    (IDM.EQ.15.AND.ID.LE.12.AND.ID.GE.7.AND.((IDM2.GE.413.AND.
+     &     IDM2.LE.418).OR.IDM2.EQ.449.OR.IDM2.
+     &     EQ.405.OR.IDM2.EQ.406))) THEN
+          IF(JMOHEP(2,CLSAVE(1)).EQ.MHEP) THEN
+            IF(IDHW(CLSAVE(1)).NE.13.AND.IDHW(CLSAVE(1)).NE.449)
+     &                       JMOHEP(2,CLSAVE(2)) = THEP
+            JDAHEP(2,MHEP) = CLSAVE(1)
+            JDAHEP(2,THEP) = CLSAVE(2)
+          ELSE
+            IF(IDHW(CLSAVE(1)).NE.13.AND.IDHW(CLSAVE(1)).NE.449)
+     &                       JMOHEP(2,CLSAVE(2)) = MHEP
+            JDAHEP(2,MHEP) = CLSAVE(2)
+            JDAHEP(2,THEP) = CLSAVE(1)
+          ENDIF
+        ELSEIF((ID.GT.6.AND.ID.LE.12.
+     &     AND.((IDM.GE.413.AND.IDM.LE.418).OR.IDM.EQ.405.OR.
+     &     IDM.EQ.406).AND.
+     &      ((IDM2.GE.419.AND.IDM2.LE.424).OR.IDM2.EQ.449.OR.
+     &      IDM2.EQ.411.OR.IDM2.EQ.412)).OR.
+     &        (ID.GT.6.AND.ID.LE.12.AND.IDM.EQ.449.
+     &   AND.((IDM2.GE.419.AND.IDM2.LE.424).OR.IDM2.EQ.449.OR.
+     &       IDM2.EQ.411.OR.IDM2.EQ.412)).OR.
+     &    (IDM.EQ.15.AND.ID.LE.6.AND.((IDM2.GE.419.AND.
+     &     IDM2.LE.424).OR.IDM2.EQ.449.OR.IDM2.EQ.411.OR.
+     &     IDM2.EQ.412))) THEN
+          IF(JDAHEP(2,CLSAVE(1)).EQ.MHEP) THEN
+            JDAHEP(2,CLSAVE(2))=THEP
+            JMOHEP(2,MHEP)=CLSAVE(1)
+            JMOHEP(2,THEP)=CLSAVE(2)
+          ELSE
+            JDAHEP(2,CLSAVE(2))=MHEP
+            JMOHEP(2,MHEP)=CLSAVE(2)
+            JMOHEP(2,THEP)=CLSAVE(1)
+          ENDIF
+        ENDIF
+        COLUPD = .FALSE.
+        CALL HWBCON
+      ENDIF
+      IF (IHEP.EQ.NHEP) GOTO 70
+  60  CONTINUE
+  70  IF (FOUND) THEN
+C Fix any SUSY colour disconnections
+        DO 80 IHEP=1,NHEP
+          IF (ISTHEP(IHEP).GE.147.AND.ISTHEP(IHEP).LE.151
+     &      .AND.JDAHEP(2,IHEP).EQ.0) THEN
+            IM=JMOHEP(1,IHEP)
+C Chase connection back through SUSY decays
+  75        IM=JMOHEP(1,IM)
+            ISM=ISTHEP(IM)
+            IF (ISM.EQ.120) GOTO 80
+            IF (ISM.NE.123.AND.ISM.NE.124.AND.ISM.NE.155) GOTO 75
+C Look for unclustered parton to connect
+            DO JHEP=1,NHEP
+              IF (ISTHEP(JHEP).GE.147.AND.ISTHEP(JHEP).LE.151) THEN
+                JCM=JMOHEP(2,JHEP)
+                IF (JCM.EQ.IM) THEN
+C Found it: connect
+                  JMOHEP(2,JHEP)=IHEP
+                  JDAHEP(2,IHEP)=JHEP
+                  GOTO 80
+                ENDIF
+              ENDIF
+            ENDDO
+C Not found: need to go further back
+            GOTO 75
+          ENDIF
+   80   CONTINUE
+C Go back to check for further heavy decay products
+        GOTO 10
+      ENDIF
+  999 END
+CDECK  ID>, HWDHVY.
+*CMZ :-        -26/04/91  12.19.24  by  Federico Carminati
+*-- Author :    Ian Knowles & Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDHVY
+C-----------------------------------------------------------------------
+C     Performs partonic decays of hadrons containing heavy quark(s):
+C     either, meson/baryon spectator model weak decays;
+C     or, quarkonia -> 2-gluons, q-qbar, 3-gluons, or 2-gluons + photon.
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION HWULDO,HWR,XS,XB,EMWSQ,GMWSQ,EMLIM,PW(4),
+     & EMTST,X1,X2,X3,TEST,HWDWWT,HWDPWT
+      INTEGER IST(3),I,IHEP,IM,ID,IDQ,IQ,IS,J
+      EXTERNAL HWR,HWDWWT,HWDPWT,HWULDO
+      DATA IST/113,114,114/
+      IF (IERROR.NE.0) RETURN
+      DO 100 I=1,NMXQDK
+      IF (I.GT.NQDK) THEN
+        NQDK=0
+        RETURN
+      ENDIF
+      IHEP=LOCQ(I)
+      IF (ISTHEP(IHEP).EQ.199) GOTO 100
+      IM=IMQDK(I)
+      IF (NHEP+NPRODS(IM).GT.NMXHEP) CALL HWWARN('HWDHVY',100,*999)
+      IF (IDKPRD(4,IM).NE.0) THEN
+C Weak decay of meson or baryon
+C Idenitify decaying heavy quark and spectator
+        ID=IDHW(IHEP)
+        IF (ID.EQ.136.OR.ID.EQ.140.OR.ID.EQ.144.OR.
+     &      ID.EQ.150.OR.ID.EQ.155.OR.ID.EQ.158.OR.ID.EQ.161.OR.
+     &     (ID.EQ.254.AND.IDKPRD(4,IM).EQ.11)) THEN
+C c hadron or c decay of B_c+
+          IDQ=4
+          IQ=NHEP+1
+          IS=NHEP+2
+        ELSEIF (ID.EQ.171.OR.ID.EQ.175.OR.ID.EQ.179.OR.
+     &          ID.EQ.185.OR.ID.EQ.190.OR.ID.EQ.194.OR.ID.EQ.196.OR.
+     &         (ID.EQ.230.AND.IDKPRD(4,IM).EQ.5)) THEN
+C cbar hadron or cbar decay of B_c-
+          IDQ=10
+          IS=NHEP+1
+          IQ=NHEP+2
+        ELSEIF ((ID.GE.221.AND.ID.LE.229).OR.
+     &          (ID.EQ.230.AND.IDKPRD(4,IM).EQ.10)) THEN
+C b hadron or b decay of B_c-
+          IDQ=5
+          IQ=NHEP+1
+          IS=NHEP+2
+        ELSEIF ((ID.GE.245.AND.ID.LE.253).OR.
+     &          (ID.EQ.254.AND.IDKPRD(4,IM).EQ.4)) THEN
+C bbar hadron or bbar decay of B_c+
+          IDQ=11
+          IS=NHEP+1
+          IQ=NHEP+2
+        ELSE
+C Decay not recognized
+          CALL HWWARN('HWDHVY',101,*999)
+        ENDIF
+C Label constituents
+        IF (NHEP+5.GT.NMXHEP) CALL HWWARN('HWDHVY',102,*999)
+        ISTHEP(IHEP)=199
+        JDAHEP(1,IHEP)=NHEP+1
+        JDAHEP(2,IHEP)=NHEP+2
+        IDHW(IQ)=IDQ
+        IDHW(IS)=IDKPRD(4,IM)
+        IDHEP(IQ)=IDPDG(IDQ)
+        IDHEP(IS)=IDPDG(IDKPRD(4,IM))
+        ISTHEP(IQ)=155
+        ISTHEP(IS)=115
+        JMOHEP(1,IQ)=IHEP
+        JMOHEP(2,IQ)=IS
+        JDAHEP(1,IQ)=NHEP+3
+        JDAHEP(2,IQ)=NHEP+5
+        JMOHEP(1,IS)=IHEP
+        JMOHEP(2,IS)=NHEP+5
+        JDAHEP(1,IS)=0
+        JDAHEP(2,IS)=NHEP+5
+        NHEP=NHEP+2
+C and weak decay product jets
+        DO 10 J=1,3
+        NHEP=NHEP+1
+        IDHW(NHEP)=IDKPRD(J,IM)
+        IDHEP(NHEP)=IDPDG(IDKPRD(J,IM))
+        ISTHEP(NHEP)=IST(J)
+        JMOHEP(1,NHEP)=IQ
+        JDAHEP(1,NHEP)=0
+  10    PHEP(5,NHEP)=RMASS(IDKPRD(J,IM))
+        JMOHEP(2,NHEP-2)=NHEP-1
+        JDAHEP(2,NHEP-2)=NHEP-1
+        JMOHEP(2,NHEP-1)=NHEP-2
+        JDAHEP(2,NHEP-1)=NHEP-2
+        JMOHEP(2,NHEP  )=IQ
+        JDAHEP(2,NHEP  )=IQ
+C Share momenta in ratio of masses, preserving specator mass
+        XS=RMASS(IDHW(IS))/PHEP(5,IHEP)
+        XB=ONE-XS
+        CALL HWVSCA(5,XB,PHEP(1,IHEP),PHEP(1,IQ))
+        CALL HWVSCA(5,XS,PHEP(1,IHEP),PHEP(1,IS))
+        IF (NME(IM).EQ.100) THEN
+C Generate decay momenta using full (V-A)*(V-A) matrix element
+          EMWSQ=RMASS(198)**2
+          GMWSQ=(RMASS(198)*GAMW)**2
+          EMLIM=GMWSQ+(EMWSQ-(PHEP(5,IQ)-PHEP(5,NHEP))**2)**2
+  20      CALL HWDTHR(PHEP(1,IQ  ),PHEP(1,NHEP-1),
+     &                PHEP(1,NHEP-2),PHEP(1,NHEP),HWDWWT)
+          CALL HWVSUM(4,PHEP(1,NHEP-2),PHEP(1,NHEP-1),PW)
+          EMTST=(HWULDO(PW,PW)-EMWSQ)**2
+          IF ((EMTST+GMWSQ)*HWR().GT.EMLIM) GOTO 20
+        ELSE
+C Use phase space
+          CALL HWDTHR(PHEP(1,IQ  ),PHEP(1,NHEP-2),
+     &                PHEP(1,NHEP-1),PHEP(1,NHEP),HWDPWT)
+          CALL HWVSUM(4,PHEP(1,NHEP-2),PHEP(1,NHEP-1),PW)
+        ENDIF
+C Set up production vertices
+        CALL HWVZRO(4,VHEP(1,IQ))
+        CALL HWVEQU(4,VHEP(1,IQ),VHEP(1,IS))
+        CALL HWVEQU(4,VHEP(1,IQ),VHEP(1,NHEP))
+        CALL HWUDKL(198,PW,VHEP(1,NHEP-2))
+        CALL HWVSUM(4,VHEP(1,IQ),VHEP(1,NHEP-2),VHEP(1,NHEP-2))
+        CALL HWVEQU(4,VHEP(1,NHEP-2),VHEP(1,NHEP-1))
+        EMSCA=PHEP(5,IQ)
+      ELSE
+C Quarkonium decay
+C Label products
+        ISTHEP(IHEP)=199
+        JDAHEP(1,IHEP)=NHEP+1
+        DO 30 J=1,NPRODS(IM)
+        NHEP=NHEP+1
+        IDHW(NHEP)=IDKPRD(J,IM)
+        IDHEP(NHEP)=IDPDG(IDKPRD(J,IM))
+        ISTHEP(NHEP)=IST(J)
+        JMOHEP(1,NHEP)=IHEP
+        JDAHEP(1,NHEP)=0
+        PHEP(5,NHEP)=RMASS(IDKPRD(J,IM))
+  30    CALL HWVZRO(4,VHEP(1,NHEP))
+        JDAHEP(2,IHEP)=NHEP
+C Establish colour connections and select momentum configuration
+        IF (NPRODS(IM).EQ.3) THEN
+          IF (IDKPRD(3,IM).EQ.13) THEN
+C 3-gluon decay
+            JMOHEP(2,NHEP-2)=NHEP
+            JMOHEP(2,NHEP-1)=NHEP-2
+            JMOHEP(2,NHEP  )=NHEP-1
+            JDAHEP(2,NHEP-2)=NHEP-1
+            JDAHEP(2,NHEP-1)=NHEP
+            JDAHEP(2,NHEP  )=NHEP-2
+          ELSE
+C or 2-gluon + photon decay
+            JMOHEP(2,NHEP-2)=NHEP-1
+            JMOHEP(2,NHEP-1)=NHEP-2
+            JMOHEP(2,NHEP  )=NHEP
+            JDAHEP(2,NHEP-2)=NHEP-1
+            JDAHEP(2,NHEP-1)=NHEP-2
+            JDAHEP(2,NHEP  )=NHEP
+          ENDIF
+          IF (NME(IM).EQ.130) THEN
+C Use Ore & Powell orthopositronium matrix element
+  40        CALL HWDTHR(PHEP(1,IHEP),PHEP(1,NHEP-2),
+     &                               PHEP(1,NHEP-1),PHEP(1,NHEP),HWDPWT)
+            X1=TWO*HWULDO(PHEP(1,IHEP),PHEP(1,NHEP-2))/PHEP(5,IHEP)**2
+            X2=TWO*HWULDO(PHEP(1,IHEP),PHEP(1,NHEP-1))/PHEP(5,IHEP)**2
+            X3=TWO-X1-X2
+            TEST=((X1*(ONE-X1))**2+(X2*(ONE-X2))**2+(X3*(ONE-X3))**2)
+     &          /(X1*X2*X3)**2
+            IF (TEST.LT.TWO*HWR()) GOTO 40
+          ELSE
+C Use phase space
+            CALL HWDTHR(PHEP(1,IHEP),PHEP(1,NHEP-2),
+     &                               PHEP(1,NHEP-1),PHEP(1,NHEP),HWDPWT)
+          ENDIF
+        ELSE
+C Parapositronium 2-gluon or q-qbar decay
+          JMOHEP(2,NHEP-1)=NHEP
+          JMOHEP(2,NHEP  )=NHEP-1
+          JDAHEP(2,NHEP-1)=NHEP
+          JDAHEP(2,NHEP  )=NHEP-1
+          CALL HWDTWO(PHEP(1,IHEP),PHEP(1,NHEP-1),
+     &                             PHEP(1,NHEP),CMMOM(IM),TWO,.FALSE.)
+        ENDIF
+        EMSCA=PHEP(5,IHEP)
+      ENDIF
+C Process this new hard scatter
+      CALL HWVEQU(4,VTXQDK(1,I),VTXPIP)
+      CALL HWBGEN
+      CALL HWCFOR
+      CALL HWCDEC
+      CALL HWDHAD
+  100 CONTINUE
+      NQDK=0
+  999 END
+CDECK  ID>, HWDRCL.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDRCL(IHEP,MHEP,CLSAVE)
+C-----------------------------------------------------------------------
+C     Sets the colour connections in Baryon number violating decays
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      INTEGER IHEP,MHEP,ID,ID2,IDM2,IDM3,COLCON(2,2,3),FLACON(2,3),JHEP,
+     &        DECAY,COLANT,KHEP,IDM,IDMB,IDMB2,IDMB3,IDMB4,QHEP,IDM4,
+     &        CLSAVE(2),XHEP,I,HWRINT,THEP
+      LOGICAL CONBV
+C--Colour connections for the decays
+      DATA COLCON/-1,1,-1,-2,-2,1,-3,-1,-1,1,-2,-1/
+      DATA FLACON/1,-1,1,-1,-1,0/
+C--identify the decay
+      IF(IERROR.NE.0) RETURN
+      ID = IDHW(IHEP)
+      ID2 = IDHW(MHEP)
+      IF(ID.GE.450.AND.ID.LE.457) THEN
+        DECAY = 1
+      ELSEIF(ID.EQ.449) THEN
+        DECAY = 2
+      ELSEIF((ID.GE.411.AND.ID.LE.424).OR.ID.EQ.405.OR.ID.EQ.406) THEN
+        DECAY = 3
+      ELSE
+C--UNKNOWN DECAY
+        CALL HWWARN('HWDRCL',100,*999)
+      ENDIF
+      COLANT = 1
+C--identify the colour partner
+      IF(DECAY.GT.1.AND.ID2.LE.6) THEN
+C--colour partner
+        COLANT = 2
+        KHEP = JDAHEP(2,IHEP-1)
+      ELSEIF(DECAY.GT.1.AND.ID2.GE.7) THEN
+C--anticolour partner
+        COLANT = 3
+        KHEP = JMOHEP(2,IHEP)
+      ELSE
+        KHEP=IHEP
+      ENDIF
+      IDM   = IDHW(JMOHEP(1,KHEP))
+      IF(ABS(IDPDG(IDM)).GT.1000000.OR.IDM.EQ.15) THEN
+        IDM2  = IDHW(JDAHEP(1,JMOHEP(1,KHEP)))
+        IDM3  = IDHW(JDAHEP(2,JMOHEP(1,KHEP)))
+        IDM4  = IDHW(JDAHEP(2,JMOHEP(1,KHEP))-1)
+        QHEP  = JMOHEP(1,KHEP)
+        IDMB  = IDHW(JMOHEP(1,QHEP))
+        IDMB2 = IDHW(JMOHEP(2,QHEP))
+        IDMB3 = IDHW(JDAHEP(1,QHEP))
+        IDMB4 = IDHW(JDAHEP(2,QHEP))
+      ENDIF
+C--Now decide if the colour partner decayed via BV
+      IF(COLANT.EQ.2.AND.((((IDM.GE.413.AND.IDM.LE.418).OR.
+     &                     IDM.EQ.449.OR.IDM.EQ.405.OR.IDM.EQ.406).AND.
+     &                       (IDM2.GE.7.AND.IDM2.LE.12.AND.
+     &                       IDM3.GE.7.AND.IDM3.LE.12.AND.
+     &                       IDM4.GE.7.AND.IDM4.LE.12)).OR.
+     &             (IDM.EQ.15.AND.IDMB.LE.6.AND.IDMB2.LE.6.AND.
+     &              ((IDMB3.GE.7.AND.IDMB4.GE.12.AND.IDMB4.EQ.449).OR.
+     &               (IDMB3.GE.198.AND.IDMB3.LE.207.AND.
+     &                ABS(IDPDG(IDMB4)).GT.1000000))))) THEN
+        CONBV = .TRUE.
+        COLUPD = .TRUE.
+        HVFCEN = .FALSE.
+        XHEP = JMOHEP(2,JDAHEP(2,JMOHEP(1,KHEP)))
+      ELSEIF(COLANT.EQ.3.AND.((((IDM.GE.419.AND.IDM.LE.424).OR.
+     &                   IDM.EQ.449.OR.IDM.EQ.411.OR.IDM.EQ.412).AND.
+     &                    (IDM2.LE.6.AND.IDM3.LE.6.AND.IDM4.LE.6)).OR.
+     &               (IDM.EQ.15.AND.IDMB.GE.7.AND.IDMB.LE.12.AND.
+     &                IDMB2.GE.7.AND.IDMB2.LE.12.AND.((IDMB3.LE.6.AND.
+     &                IDMB4.EQ.449).OR.(ABS(IDPDG(IDMB4)).GT.1000000
+     &                .AND.IDMB3.GE.198.AND.IDMB3.LE.207))))) THEN
+        CONBV = .TRUE.
+        COLUPD = .TRUE.
+        HVFCEN = .FALSE.
+        XHEP = JDAHEP(2,JDAHEP(2,JMOHEP(1,KHEP)))
+      ELSE
+        CONBV = .FALSE.
+        COLUPD = .FALSE.
+        XHEP = 0
+      ENDIF
+      IF(CONBV) THEN
+        IF(IDM.NE.15) THEN
+          CLSAVE(1) = JDAHEP(2,JMOHEP(1,KHEP))-1
+          CLSAVE(2) = CLSAVE(1)+1
+        ELSE
+          IF(IDMB4.EQ.449) THEN
+            DO I=1,2
+              CLSAVE(I) = JMOHEP(I,JMOHEP(1,KHEP))
+              IF(CLSAVE(I).EQ.XHEP) CLSAVE(I)=JDAHEP(1,JMOHEP(1,KHEP))
+            ENDDO
+          ELSE
+            CLSAVE(1) = JMOHEP(1,JMOHEP(1,KHEP))
+            CLSAVE(2) = JMOHEP(2,JMOHEP(1,KHEP))
+          ENDIF
+        ENDIF
+      ELSE
+        CLSAVE(1)=0
+        CLSAVE(2)=0
+      ENDIF
+C--Now set the colours for angular ordering
+      THEP = MHEP-1
+      IF(DECAY.EQ.1) THEN
+        IF(ID2.LE.6) THEN
+          JMOHEP(2,THEP) = THEP+HWRINT(1,2)
+          JDAHEP(2,THEP) = THEP
+        ELSE
+          JMOHEP(2,THEP) = THEP
+          JDAHEP(2,THEP) = THEP+HWRINT(1,2)
+        ENDIF
+      ELSEIF(DECAY.EQ.2) THEN
+        IF(ID2.LE.6) THEN
+          JMOHEP(2,THEP) = IHEP
+          JDAHEP(2,THEP) = THEP
+        ELSE
+          JMOHEP(2,THEP) = THEP
+          JDAHEP(2,THEP) = IHEP
+        ENDIF
+      ENDIF
+C--Colour of the second two
+      DO JHEP=1,2
+        IF(ID2.LE.6) THEN
+          JMOHEP(2,MHEP+JHEP-1) = MHEP+JHEP-1+
+     &                           COLCON(HWRINT(1,2),JHEP,DECAY)
+          JDAHEP(2,MHEP+JHEP-1) = MHEP+JHEP-1+FLACON(JHEP,DECAY)
+        ELSE
+          JDAHEP(2,MHEP+JHEP-1) = MHEP+JHEP-1+
+     &                           COLCON(HWRINT(1,2),JHEP,DECAY)
+          JMOHEP(2,MHEP+JHEP-1) = MHEP+JHEP-1+FLACON(JHEP,DECAY)
+        ENDIF
+      ENDDO
+C--Now set the colours of the colour partner
+      IF(DECAY.GT.1.AND..NOT.CONBV) THEN
+        IF(ID2.LE.6) JMOHEP(2,KHEP) = MHEP+HWRINT(0,1)
+        IF(ID2.GE.7) JDAHEP(2,KHEP) = MHEP+HWRINT(0,1)
+      ELSEIF(CONBV) THEN
+        IF(ID2.GT.6) THEN
+          JMOHEP(2,CLSAVE(1)) = MHEP+HWRINT(0,1)
+          IF(JMOHEP(2,CLSAVE(1)).EQ.MHEP) THEN
+            JMOHEP(2,CLSAVE(2)) = MHEP+1
+          ELSE
+            JMOHEP(2,CLSAVE(2)) = MHEP
+          ENDIF
+        ELSE
+          JDAHEP(2,CLSAVE(1)) = MHEP+HWRINT(0,1)
+          IF(JDAHEP(2,CLSAVE(1)).EQ.MHEP) THEN
+            JDAHEP(2,CLSAVE(2)) = MHEP+1
+          ELSE
+            JDAHEP(2,CLSAVE(2)) = MHEP
+          ENDIF
+        ENDIF
+      ENDIF
+ 999  END
+CDECK  ID>, HWDRME.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDRME(LHEP,MHEP)
+C-----------------------------------------------------------------------
+C     SUBROUTINE TO IMPLEMENT ALL RPARITY DECAY MATRIX ELEMENTS
+C-----------------------------------------------------------------------
+      INCLUDE 'HERWIG61.INC'
+      DOUBLE PRECISION SM(6),SW(6),HWULDO,INFCOL,AM, M12SQ,M23SQ,MSGN,
+     &                 M13SQ,A(6),B(6),SWEAK,MW,DECMOM(5),TEST(4),EPS,
+     &                 M12SQT(6),M23SQT(6),M13SQT(6),LIMIT,M(4),RAND,
+     &                 MC(2),MX2(6),MX(6),HWDPWT,HWR,HWDRM1,LAMD(3)
+      EXTERNAL         HWDRM1,HWULDO,HWDPWT,HWR
+      INTEGER K,SN(3),LHEP,CSP,I,SB(3),J,ND,LTRY,MHEP,NSP,ID(3),IG,
+     &        IDHWTP,IDHPTP,MTRY
+      PARAMETER(EPS=1D-20)
+      IF(IERROR.NE.0) RETURN
+C--Electroweak parameters, etc
+      SWEAK = SQRT(SWEIN)
+      MW    = RMASS(198)
+      M(4)  = PHEP(5,LHEP)
+      IG    = IDHW(LHEP)
+C--Find the masses of the final state and zero parameters
+      DO K=1,3
+        ID(K) = IDHW(MHEP+K-1)
+        IF(ID(K).LE.12) THEN
+          SN(K)=ID(K)
+        ELSE
+          SN(K)=ID(K)-120
+        ENDIF
+        IF(SN(K).GT.6) SN(K)=SN(K)-6
+        M(K) = PHEP(5,LHEP+K)
+        SB(K)=SN(K)
+        LAMD(K) = ZERO
+      ENDDO
+      DO J=1,6
+        MX2(J) = ZERO
+        MX(J)  = ZERO
+        M13SQT(J) = ZERO
+        M23SQT(J) = ZERO
+        M12SQT(J) = ZERO
+      ENDDO
+C--Evaluate the coefficents for the mode we want
+      IF(IG.GE.450.AND.IG.LE.453) THEN
+C--NEUTRALINO
+        NSP = IG-449
+        AM = RMASS(IG)
+        MSGN = ZSGNSS(NSP)
+        MC(1) =  ZMIXSS(NSP,3)/(2*MW*COSB*SWEAK)
+        MC(2) =  ZMIXSS(NSP,4)/(2*MW*SINB*SWEAK)
+C--Calculate the combinations of couplings needed
+        IF(ID(1).LE.12.AND.ID(2).LE.12.AND.ID(3).LE.12) THEN
+C--first for the UDD modes
+          DO J=1,2
+            A(J) = M(1)*MC(2)*QMIXSS(SN(1),2,J)
+     &             +SLFCH(SN(1),NSP)*QMIXSS(SN(1),1,J)
+            B(J) = MSGN*(M(1)*MC(2)*QMIXSS(SN(1),1,J)
+     &             +SRFCH(SN(1),NSP)*QMIXSS(SN(1),2,J))
+            MX2(J) = QMIXSS(SN(1),2,J)
+            A(J+2) = M(2)*MC(1)*QMIXSS(SN(2),2,J)
+     &               +SLFCH(SN(2),NSP)*QMIXSS(SN(2),1,J)
+            B(J+2) = MSGN*(M(2)*MC(1)*QMIXSS(SN(2),1,J)
+     &               +SRFCH(SN(2),NSP)*QMIXSS(SN(2),2,J))
+            MX2(J+2) = QMIXSS(SN(2),2,J)
+            A(J+4) = M(3)*MC(1)*QMIXSS(SN(3),2,J)
+     &              +SLFCH(SN(3),NSP)*QMIXSS(SN(3),1,J)
+            B(J+4) = MSGN*(M(3)*MC(1)*QMIXSS(SN(3),1,J)
+     &              +SRFCH(SN(3),NSP)*QMIXSS(SN(3),2,J))
+            MX2(J+2) = QMIXSS(SN(3),2,J)
+          ENDDO
+          DO K=1,3
+            SN(K) = SN(K)+400
+            SB(K) = SB(K)+412
+          ENDDO
+        ELSEIF(ID(1).GE.121.AND.ID(2).GE.121.AND.ID(3).GE.121) THEN
+C--Now for the LLE modes
+          DO J=1,2
+            A(J)  = MSGN*(M(1)*MC(1)*LMIXSS(SN(1),1,J)
+     &              +SRFCH(10+SN(1),NSP)*LMIXSS(SN(1),2,J))
+            B(J)  = M(1)*MC(1)*LMIXSS(SN(1),2,J)
+     &              +SLFCH(10+SN(1),NSP)*LMIXSS(SN(2),1,J)
+            MX2(J)= LMIXSS(SN(1),1,J)
+            A(J+2) = ZERO
+            B(J+2) = SLFCH(10+SN(2),NSP)*LMIXSS(SN(2),1,J)
+            MX2(J+2) =  LMIXSS(SN(2),1,J)
+            A(J+4) = M(3)*MC(1)*LMIXSS(SN(3),2,J)
+     &      +SLFCH(10+SN(3),NSP)*LMIXSS(SN(3),1,J)
+            B(J+4) = MSGN*(M(3)*MC(1)*LMIXSS(SN(3),1,J)
+     &      +SRFCH(10+SN(3),NSP)*LMIXSS(SN(3),2,J))
+            MX2(4+J) = LMIXSS(SN(3),2,J)
+          ENDDO
+          DO J=1,3
+            SN(J) = SN(J) + 424
+            SB(J) = SB(J) + 436
+          ENDDO
+        ELSE
+C--Now for both types of LQD modes
+          IF(MOD(SN(1),2).EQ.0) THEN
+C--First the neutrino,down,antidown mode
+            DO J=1,2
+              A(J) = ZERO
+              B(J) = SLFCH(10+SN(1),NSP)*
+     &               LMIXSS(SN(1),1,J)
+              MX2(J) = LMIXSS(SN(1),1,J)
+              A(J+2) = MSGN*(M(2)*MC(1)*QMIXSS(SN(2),1,J)
+     &        +SRFCH(SN(2),NSP)*QMIXSS(SN(2),2,J))
+              B(J+2) = M(2)*MC(1)*QMIXSS(SN(2),2,J)
+     &        +SLFCH(SN(2),NSP)*QMIXSS(SN(2),1,J)
+              MX2(2+J) = QMIXSS(SN(2),1,J)
+              A(J+4) = M(3)*MC(1)*QMIXSS(SN(3),2,J)
+     &        +SLFCH(SN(3),NSP)*QMIXSS(SN(3),1,J)
+              B(J+4) = MSGN*(M(3)*MC(1)*QMIXSS(SN(3),1,J)
+     &        +SRFCH(SN(3),NSP)*QMIXSS(SN(3),2,J))
+              MX2(J+4) = QMIXSS(SN(3),2,J)
+            ENDDO
+          ELSE
+C--Now the charged lepton, antiup,down modes
+            DO J=1,2
+              A(J) = MSGN*(M(1)*MC(1)*LMIXSS(SN(1),1,J)
+     &        +SRFCH(10+SN(1),NSP)*LMIXSS(SN(1),2,J))
+              B(J) = M(1)*MC(1)*LMIXSS(SN(1),2,J)
+     &        +SLFCH(10+SN(1),NSP)*LMIXSS(SN(1),1,J)
+              MX2(J) = LMIXSS(SN(1),1,J)
+              A(J+2) =MSGN*(M(2)*MC(2)*QMIXSS(SN(2),1,J)
+     &        +SRFCH(SN(2),NSP)*QMIXSS(SN(2),2,J))
+              B(J+2) = M(2)*MC(2)*QMIXSS(SN(2),2,J)
+     &        +SLFCH(SN(2),NSP)*QMIXSS(SN(2),1,J)
+              MX2(2+J) = QMIXSS(SN(2),1,J)
+              A(J+4) = M(3)*MC(1)*QMIXSS(SN(3),2,J)
+     &        +SLFCH(SN(3),NSP)*QMIXSS(SN(3),1,J)
+              B(J+4) = MSGN*(M(3)*MC(1)*QMIXSS(SN(3),1,J)
+     &        +SRFCH(SN(3),NSP)*QMIXSS(SN(3),2,J))
+              MX2(J+4) = QMIXSS(SN(3),2,J)
+            ENDDO
+          ENDIF
+          SN(1) = SN(1) + 424
+          SB(1) = SB(1) + 436
+          DO J=2,3
+            SN(J) = SN(J) + 400
+            SB(J) = SB(J) + 412
+          ENDDO
+        ENDIF
+        DO K=1,3
+          SM(2*K-1) = RMASS(SN(K))
+          SM(2*K)   = RMASS(SB(K))
+          SW(2*K-1) = HBAR/RLTIM(SN(K))
+          SW(2*K)   = HBAR/RLTIM(SB(K))
+        ENDDO
+        ND = 3
+        DO K=1,3
+          LAMD(K) = ONE
+        ENDDO
+        INFCOL = ONE
+      ELSEIF(IG.EQ.449) THEN
+C--GLUINO
+C--First obtian the masses and widths needed
+        AM  = RMASS(IG)
+        ND = 3
+C--Calculate the combinations of couplings needed
+        IF(ID(1).LE.12.AND.ID(2).LE.12.AND.ID(3).LE.12) THEN
+C--first for the UDD modes
+          INFCOL = -0.5D0
+C--Couplings
+          DO I=1,3
+            DO J=1,2
+              A(2*I-2+J)  = -QMIXSS(SN(I),1,J)
+              B(2*I-2+J)  =  QMIXSS(SN(I),2,J)
+              MX2(2*I-2+J) =  QMIXSS(SN(I),2,J)
+            ENDDO
+            SN(I) = SN(I)+400
+            SB(I) = SB(I)+412
+          ENDDO
+        ELSE
+          INFCOL = ONE
+C--Now for both types of LQD modes
+          IF(MOD(SN(1),2).EQ.0) THEN
+C--First the neutrino,down,antidown mode
+            DO J=1,2
+              A(J)  = ZERO
+              B(J)  = ZERO
+              MX2(J) = ZERO
+              A(J+2)   =  QMIXSS(SN(2),2,J)
+              B(J+2)   = -QMIXSS(SN(2),1,J)
+              MX2(J+2) =  QMIXSS(SN(2),1,J)
+              A(J+4)   = -QMIXSS(SN(3),1,J)
+              B(J+4)   =  QMIXSS(SN(3),2,J)
+              MX2(4+J) =  QMIXSS(SN(3),2,J)
+            ENDDO
+          ELSEIF(MOD(SN(1),2).EQ.1) THEN
+C--Now the charged lepton, antiup,down modes
+            DO J=1,2
+              A(J)  = ZERO
+              B(J)  = ZERO
+              MX2(J) = ZERO
+              A(J+2)   =  QMIXSS(SN(2),2,J)
+              B(J+2)   = -QMIXSS(SN(2),1,J)
+              MX2(J+2) =  QMIXSS(SN(2),1,J)
+              A(J+4)     = -QMIXSS(SN(3),1,J)
+              B(J+4)   =  QMIXSS(SN(3),2,J)
+              MX2(J+4) =  QMIXSS(SN(3),2,J)
+            ENDDO
+          ENDIF
+          SN(1) = SN(1) + 424
+          SB(1) = SB(1) + 436
+          DO K=2,3
+            SN(K) = SN(K) + 400
+            SB(K) = SB(K) + 412
+          ENDDO
+        ENDIF
+        DO K=1,3
+          SM(2*K-1) = RMASS(SN(K))
+          SM(2*K)   = RMASS(SB(K))
+          SW(2*K-1) = HBAR/RLTIM(SN(K))
+          SW(2*K)   = HBAR/RLTIM(SB(K))
+        ENDDO
+        DO K=1,3
+          LAMD(K) = ONE
+        ENDDO
+      ELSEIF(IG.GE.454.AND.IG.LE.457) THEN
+C--CHARGINO
+        CSP = IG-453
+        IF(CSP.GT.2) CSP = CSP-2
+        AM  = RMASS(IG)
+        INFCOL = -ONE
+        MSGN = WSGNSS(CSP)
+        MC(1) =  ONE/(SQRT(2.0D0)*MW*COSB)
+        MC(2) =  ONE/(SQRT(2.0D0)*MW*SINB)
+C--Calculate the combinations of the couplings needed
+        IF(ID(1).GT.120.AND.ID(2).GT.120.AND.ID(3).GT.120) THEN
+C--first for the LLE modes, three modes
+          IF(MOD(SN(1),2).EQ.0.AND.MOD(SN(3),2).EQ.0) THEN
+C--the one diagram mode nubar,positron, nu
+            DO J=1,2
+              A(J+4) = LMIXSS(SN(3)-1,1,J)*WMXUSS(CSP,1)
+     & -RMASS(SN(3)+119)*MC(1)*LMIXSS(SN(3)-1,2,J)*WMXUSS(CSP,2)
+              B(J+4) = ZERO
+              MX2(J+4) = LMIXSS(SN(3)-1,2,J)
+            ENDDO
+            ND = 1
+            SN(3) = SN(3)+423
+            SB(3) = SB(3)+435
+          ELSEIF(MOD(SN(1),2).EQ.0.AND.MOD(SN(2),2).EQ.0) THEN
+C--the first two diagram mode nu, nu, positron
+            DO J=1,2
+              A(J)   = ZERO
+              B(J)   = LMIXSS(SN(1)-1,1,J)*WMXUSS(CSP,1)
+     & -RMASS(SN(1)+119)*MC(1)*LMIXSS(SN(1)-1,2,J)*WMXUSS(CSP,2)
+              A(J+2) = ZERO
+              B(J+2) = LMIXSS(SN(2)-1,1,J)*WMXUSS(CSP,1)
+     & -RMASS(SN(2)+119)*MC(1)*LMIXSS(SN(2)-1,2,J)*WMXUSS(CSP,2)
+              MX2(J)   = LMIXSS(SN(1)-1,1,J)
+              MX2(J+2) = LMIXSS(SN(2)-1,1,J)
+            ENDDO
+            ND = 2
+            DO J=1,2
+              SN(J) = SN(J)+423
+              SB(J) = SB(J)+435
+            ENDDO
+          ELSE
+C--the second two diagram mode positron, positron, electron
+            DO J=1,2
+              A(J)   = -M(1)*WMXUSS(CSP,2)*MC(1)*LMIXSS(SN(1)+1,1,J)
+              B(J)   = MSGN*WMXVSS(CSP,1)*LMIXSS(SN(1)+1,1,J)
+              A(J+2) = -M(2)*WMXUSS(CSP,2)*MC(1)*LMIXSS(SN(2)+1,1,J)
+              B(J+2) = MSGN*WMXVSS(CSP,1)*LMIXSS(SN(2)+1,1,J)
+              MX2(J)   = LMIXSS(SN(1)+1,1,J)
+              MX2(J+2) = LMIXSS(SN(2)+1,1,J)
+            ENDDO
+            DO J=1,2
+              SN(J) = SN(J)+425
+              SB(J) = SB(J)+437
+            ENDDO
+            ND = 2
+          ENDIF
+          DO K=1,3
+            LAMD(K) = ONE
+          ENDDO
+        ELSEIF(ID(1).LE.12.AND.ID(2).LE.12.AND.ID(3).LE.12) THEN
+C--now for the UDD
+          IF(MOD(SN(1),2).EQ.0) THEN
+C--two diagram mode
+            LAMD(1) = LAMDA3(SN(2)/2,SN(1)/2,(SN(3)+1)/2)
+            LAMD(2) = LAMDA3(SN(1)/2,SN(2)/2,(SN(3)+1)/2)
+            DO J=1,2
+              A(J)   = WMXUSS(CSP,1)*QMIXSS(SN(1)-1,1,J)
+     & -RMASS(SN(1)-1)*MC(1)*WMXUSS(CSP,2)*QMIXSS(SN(1)-1,2,J)
+              B(J)   = -MSGN*M(2)*WMXVSS(CSP,2)*QMIXSS(SN(1)-1,1,J)
+              A(J+2) = WMXUSS(CSP,1)*QMIXSS(SN(2)-1,1,J)
+     & -RMASS(SN(2)-1)*MC(1)*WMXUSS(CSP,2)*QMIXSS(SN(2)-1,2,J)
+              B(J+2) = -MSGN*M(2)*WMXVSS(CSP,2)*QMIXSS(SN(2)-1,1,J)
+              MX2(J)   = QMIXSS(SN(1)-1,2,J)
+              MX2(J+2) = QMIXSS(SN(2)-1,2,J)
+            ENDDO
+            DO J=1,2
+              SN(J) = SN(J) + 399
+              SB(J) = SB(J) + 411
+            ENDDO
+            ND = 2
+          ELSE
+C--three diagram mode
+            LAMD(1) = LAMDA3((SN(1)+1)/2,(SN(2)+1)/2,(SN(3)+1)/2)
+            LAMD(2) = LAMDA3((SN(2)+1)/2,(SN(1)+1)/2,(SN(3)+1)/2)
+            LAMD(3) = LAMDA3((SN(3)+1)/2,(SN(2)+1)/2,(SN(1)+1)/2)
+            DO I=1,3
+              DO J=1,2
+                A(J+2*I-2) = MSGN*(WMXVSS(CSP,1)*QMIXSS(SN(I)+1,1,J)
+     & -RMASS(SN(I)+1)*MC(2)*WMXVSS(CSP,2)*QMIXSS(SN(I)+1,2,J))
+                B(J+2*I-2) = -M(I)*MC(1)*WMXUSS(CSP,2)
+     &                       *QMIXSS(SN(I)+1,1,J)
+                MX2(J+2*I-2)   = QMIXSS(SN(I)+1,2,J)
+              ENDDO
+              SN(I) = SN(I) + 401
+              SB(I) = SB(I) + 413
+            ENDDO
+            ND = 3
+          ENDIF
+        ELSE
+C--now for the LQD modes
+          IF(MOD(SN(2),2).EQ.1.AND.MOD(SN(3),2).EQ.0) THEN
+C--first one diagram mode nubar, dbar, up
+            DO J=1,2
+              A(J+4) = -MSGN*M(3)*WMXVSS(CSP,2)*MC(2)*
+     &                  QMIXSS(SN(3)-1,1,J)
+              B(J+4) = WMXUSS(CSP,1)*QMIXSS(SN(3)-1,1,J)
+     &        -RMASS(SN(3)-1)*MC(1)*WMXUSS(CSP,2)*QMIXSS(SN(3)-1,2,1)
+              MX2(J+4)   = QMIXSS(SN(3)-1,2,J)
+            ENDDO
+            SN(3) = SN(3) + 399
+            SB(3) = SB(3) + 411
+            ND = 1
+          ELSEIF(MOD(SN(2),2).EQ.0.AND.MOD(SN(3),2).EQ.0) THEN
+C--second one diagram mode positron, ubar, up
+            DO J=1,2
+              A(J+4) = -MSGN*M(3)*WMXVSS(CSP,2)*MC(2)*
+     &                  QMIXSS(SN(3)-1,1,J)
+              B(J+4) = WMXUSS(CSP,1)*QMIXSS(SN(3)-1,1,J)
+     &   -RMASS(SN(3)-1)*MC(1)*WMXUSS(CSP,2)*QMIXSS(SN(3)-1,2,1)
+              MX2(J+4)   = QMIXSS(SN(3)-1,2,J)
+            ENDDO
+            SN(3) = SN(3) + 399
+            SB(3) = SB(3) + 411
+            ND = 1
+          ELSEIF(MOD(SN(2),2).EQ.1.AND.MOD(SN(3),2).EQ.1) THEN
+C--first two diagram mode positron, dbar, down
+            DO J=1,2
+              A(J)   = -M(1)*MC(1)*WMXUSS(CSP,2)*LMIXSS(SN(1)+1,1,J)
+              B(J)   = MSGN*WMXVSS(CSP,1)*LMIXSS(SN(2)+1,1,J)
+              A(J+2) = -M(2)*WMXUSS(CSP,2)*MC(1)*QMIXSS(SN(2)+1,1,J)
+              B(J+2) = MSGN*(WMXVSS(CSP,1)*QMIXSS(SN(2)+1,1,J)
+     &   -RMASS(SN(2)+1)*MC(2)*WMXVSS(CSP,2)*QMIXSS(SN(2)+1,2,J))
+              MX2(J)   = LMIXSS(SN(1)+1,1,J)
+              MX2(J+2) = QMIXSS(SN(2)+1,1,J)
+            ENDDO
+            SN(1) = SN(1) + 425
+            SB(1) = SB(1) + 437
+            SN(2) = SN(2) + 401
+            SB(2) = SB(2) + 413
+            ND = 2
+          ELSE
+C--second two diagram mode nu, up, dbar
+            DO J=1,2
+              A(J)   = ZERO
+              B(J)   = WMXUSS(CSP,1)*LMIXSS(SN(1)-1,1,J)
+     &   -RMASS(119+SN(1))*MC(1)*WMXUSS(CSP,2)*LMIXSS(SN(1)-1,2,J)
+              A(J+2) = -MSGN*M(2)*MC(2)*WMXVSS(CSP,2)*
+     &                 QMIXSS(SN(2)-1,1,J)
+              B(J+2) = WMXUSS(CSP,1)*QMIXSS(SN(2)-1,1,J)
+     &   -RMASS(SN(2)-1)*MC(1)*WMXUSS(CSP,2)*QMIXSS(SN(2)-1,2,J)
+              MX2(J)   = LMIXSS(SN(1)-1,1,J)
+              MX2(J+2) = QMIXSS(SN(2)-1,1,J)
+            ENDDO
+            SN(1) = SN(1) + 423
+            SB(1) = SB(1) + 435
+            SN(2) = SN(2) + 399
+            SB(2) = SB(2) + 411
+            ND = 2
+          ENDIF
+          DO K=1,3
+            LAMD(K) = ONE
+          ENDDO
+        ENDIF
+        IF(ND.EQ.1) THEN
+          DO K=1,2
+            SM(2*K-1) = 0.0D0
+            SM(2*K)   = 0.0D0
+            SW(2*K-1) = 0.0D0
+            SW(2*K)   = 0.0D0
+          ENDDO
+          SM(5) = RMASS(SN(3))
+          SM(6)   = RMASS(SB(3))
+          SW(5) = HBAR/RLTIM(SN(3))
+          SW(6)   = HBAR/RLTIM(SB(3))
+        ELSE
+          DO K=1,2
+            SM(2*K-1) = RMASS(SN(K))
+            SM(2*K)   = RMASS(SB(K))
+            SW(2*K-1) = HBAR/RLTIM(SN(K))
+            SW(2*K)   = HBAR/RLTIM(SB(K))
+            SM(4+K)   = ZERO
+            SW(4+K)   = ZERO
+          ENDDO
+        ENDIF
+      ELSE
+C--UNKNOWN
+        CALL HWWARN('HWDRME',500,*999)
+      ENDIF
+C--Set mixing to zero if diagram not available
+      IF((AM.LT.(ABS(SM(1))+M(1)).OR.ABS(SM(1)).LT.(M(2)+M(3)))
+     &   .AND.ABS(MX2(1)).GT.ZERO.AND.ND.NE.1) MX(1) = MX2(1)*LAMD(1)
+        IF((AM.LT.(ABS(SM(2))+M(1)).OR.ABS(SM(2)).LT.(M(2)+M(3)))
+     &   .AND.ABS(MX2(2)).GT.ZERO.AND.ND.NE.1) MX(2) = MX2(2)*LAMD(1)
+        IF((AM.LT.(ABS(SM(3))+M(2)).OR.ABS(SM(3)).LT.(M(1)+M(3)))
+     &   .AND.ABS(MX2(3)).GT.ZERO.AND.ND.NE.1) MX(3) = MX2(3)*LAMD(2)
+        IF((AM.LT.(ABS(SM(4))+M(2)).OR.ABS(SM(4)).LT.(M(1)+M(3)))
+     &   .AND.ABS(MX2(4)).GT.ZERO.AND.ND.NE.1) MX(4) = MX2(4)*LAMD(2)
+        IF((AM.LT.(ABS(SM(5))+M(3)).OR.ABS(SM(5)).LT.(M(1)+M(2)))
+     &   .AND.ABS(MX2(5)).GT.ZERO.AND.ND.NE.2) MX(5) = MX2(5)*LAMD(3)
+        IF((AM.LT.(ABS(SM(6))+M(3)).OR.ABS(SM(6)).LT.(M(1)+M(2)))
+     &   .AND.ABS(MX2(6)).GT.ZERO.AND.ND.NE.2) MX(6) = MX2(6)*LAMD(3)
+C--Calculate the limiting points
+      DO J=1,2
+        IF(ND.NE.1) THEN
+          IF(ABS(MX(J)).GT.EPS) CALL HWDRM5(M23SQT(J),M13SQT(J),
+     &      M12SQT(J),A(J),B(J),M(2),M(3),M(1),M(4),SM(J),SW(J))
+          IF(ABS(MX(J+2)).GT.EPS) CALL HWDRM5(M13SQT(2+J),M23SQT(2+J),
+     &    M12SQT(2+J),A(2+J),B(2+J),M(1),M(3),M(2),M(4),SM(2+J),SW(2+J))
+        ENDIF
+        IF(ND.NE.2) THEN
+          IF(ABS(MX(J+4)).GT.EPS) CALL HWDRM5(M12SQT(4+J),M23SQT(4+J),
+     &    M13SQT(4+J),A(4+J),B(4+J),M(1),M(2),M(3),M(4),SM(4+J),SW(4+J))
+        ENDIF
+      ENDDO
+C--Now evaluate the limit using these points
+      LIMIT = ZERO
+      DO 100 I=1,6
+        IF(ABS(MX(I)).LT.EPS) GOTO 100
+        LIMIT = LIMIT+HWDRM1(TEST,M12SQT(I),M13SQT(I),M23SQT(I),A,B,MX,
+     &                       M,SM,SW,INFCOL,AM,0,ND)
+ 100  CONTINUE
+      LIMIT = TWO*LIMIT
+C--Now evaluate at a random point
+      MTRY = 0
+ 25   MTRY = MTRY+1
+      LTRY = 0
+ 35   LTRY = LTRY+1
+      CALL HWDTHR(PHEP(1,LHEP),PHEP(1,MHEP),
+     &                  PHEP(1,MHEP+1),PHEP(1,MHEP+2),HWDPWT)
+C--Now calculate the m12sq etc for the actual point
+      M12SQ = M(1)**2+M(2)**2+2*HWULDO(PHEP(1,MHEP),PHEP(1,MHEP+1))
+      M13SQ = M(1)**2+M(3)**2+2*HWULDO(PHEP(1,MHEP),PHEP(1,MHEP+2))
+      M23SQ = M(2)**2+M(3)**2+2*HWULDO(PHEP(1,MHEP+1),PHEP(1,MHEP+2))
+C--Now calulate the matrix element
+      TEST(4) = HWDRM1(TEST,M12SQ,M13SQ,M23SQ,A,B,MX,
+     &                       M,SM,SW,INFCOL,AM,1,ND)
+C--Now test the value againest the limit
+      RAND = HWR()*LIMIT
+      IF(TEST(4).GT.LIMIT) THEN
+        LIMIT = 1.1D0*TEST(4)
+        CALL HWWARN('HWDRME',51,*150)
+      ENDIF
+ 150  IF(TEST(4).LT.RAND.AND.LTRY.LT.NETRY) THEN
+        GOTO 35
+      ELSEIF(LTRY.GE.NETRY) THEN
+        IF(MTRY.LE.NETRY) THEN
+          LIMIT = LIMIT*0.9D0
+          CALL HWWARN('HWDRME',52,*25)
+        ELSE
+          CALL HWWARN('HWDRME',100,*999)
+        ENDIF
+      ENDIF
+C--Reorder the particles in gluino decay to get angular ordering right
+      IF(IG.EQ.449.AND.ID(1).LE.12.AND.ID(2).LE.12.AND.ID(3).LE.12) THEN
+        DO LTRY=1,3
+          IF(TEST(LTRY).GT.RAND) THEN
+            IF(LTRY.EQ.2) THEN
+              IDHWTP        = IDHW(MHEP)
+              IDHW(MHEP)    = IDHW(MHEP+1)
+              IDHW(MHEP+1)  = IDHWTP
+              IDHPTP        = IDHEP(MHEP)
+              IDHEP(MHEP)   = IDHEP(MHEP+1)
+              IDHEP(MHEP+1) = IDHPTP
+              CALL HWVEQU(5,PHEP(1,MHEP),DECMOM)
+              CALL HWVEQU(5,PHEP(1,MHEP+1),PHEP(1,MHEP))
+              CALL HWVEQU(5,DECMOM,PHEP(1,MHEP+1))
+            ELSEIF(LTRY.EQ.3) THEN
+              IDHWTP        = IDHW(MHEP)
+              IDHW(MHEP)    = IDHW(MHEP+2)
+              IDHW(MHEP+2)    = IDHWTP
+              IDHPTP        = IDHEP(MHEP)
+              IDHEP(MHEP)   = IDHEP(MHEP+2)
+              IDHEP(MHEP+2)   = IDHPTP
+              DO I=1,5
+              CALL HWVEQU(5,PHEP(1,MHEP),DECMOM)
+              CALL HWVEQU(5,PHEP(1,MHEP+2),PHEP(1,MHEP))
+              CALL HWVEQU(5,DECMOM,PHEP(1,MHEP+2))
+              ENDDO
+            ENDIF
+            GOTO 52
+          ENDIF
+          RAND=RAND-TEST(LTRY)
+        ENDDO
+      ENDIF
+ 52   CONTINUE
+ 999  END
+CDECK  ID>, HWDRM1.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      FUNCTION HWDRM1(TEST,M12SQ,M13SQ,M23SQ,A,B,MX,M,SM,SW
+     &                ,INFCOL,AM,LM,ND)
+C-----------------------------------------------------------------------
+C     FUNCTION TO GIVE THE R-PARITY VIOLATING MATRIX ELEMENT AT A GIVEN
+C     PHASE-SPACE POINT
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION M12SQ,M13SQ,M23SQ,MX(6),A(6),B(6),SM(6),SW(6),
+     &                 INFCOL,AM,TERM(21),TEST(4),PLN,NPLN,ZERO,
+     &                 M(4),HWDRM1,HWDRM2,HWDRM3,HWDRM4
+      PARAMETER (ZERO=0)
+      EXTERNAL HWDRM2,HWDRM3,HWDRM4
+      INTEGER LM,K,ND
+C--Zero the array
+        DO K=1,21
+          TERM(K) = 0.0D0
+        ENDDO
+        HWDRM1 = 0.0D0
+C--The amplitude
+      IF(ABS(MX(1)).GT.ZERO.AND.ND.NE.1) THEN
+        TERM(1) = MX(1)**2*HWDRM2(M23SQ,M(2),M(3),M(1),M(4),SM(1),
+     &            SW(1),A(1),B(1))
+        IF(ABS(MX(2)).GT.ZERO) TERM(7)= MX(1)*MX(2)*HWDRM3(M23SQ,M(2),
+     &   M(3),M(1),M(4),SM(1),SM(2),SW(1),SW(2),A(1),A(2),B(1),B(2))
+        IF(ABS(MX(3)).GT.ZERO) TERM(10)=-MX(1)*MX(3)*HWDRM4(M13SQ,M23SQ,
+     &  M(1),M(3),M(2),M(4),SM(3),SM(1),SW(3),SW(1),A(1),A(3),B(1),B(3))
+        IF(ABS(MX(4)).GT.ZERO) TERM(11)=-MX(1)*MX(4)*HWDRM4(M13SQ,M23SQ,
+     &  M(1),M(3),M(2),M(4),SM(4),SM(1),SW(4),SW(1),A(1),A(4),B(1),B(4))
+        IF(ABS(MX(5)).GT.ZERO) TERM(12)=-MX(1)*MX(5)*HWDRM4(M23SQ,M12SQ,
+     &  M(3),M(2),M(1),M(4),SM(1),SM(5),SW(1),SW(5),A(5),A(1),B(5),B(1))
+        IF(ABS(MX(6)).GT.ZERO) TERM(13)=-MX(1)*MX(6)*HWDRM4(M23SQ,M12SQ,
+     &  M(3),M(2),M(1),M(4),SM(1),SM(6),SW(1),SW(6),A(6),A(1),B(6),B(1))
+      ENDIF
+      IF(ABS(MX(2)).GT.ZERO.AND.ND.NE.1) THEN
+        TERM(2) = MX(2)**2*HWDRM2(M23SQ,M(2),M(3),M(1),M(4),SM(2),
+     &            SW(2),A(2),B(2))
+        IF(ABS(MX(3)).GT.ZERO) TERM(14)=-MX(2)*MX(3)*HWDRM4(M13SQ,M23SQ,
+     &  M(1),M(3),M(2),M(4),SM(3),SM(2),SW(3),SW(2),A(2),A(3),B(2),B(3))
+        IF(ABS(MX(4)).GT.ZERO) TERM(15)=-MX(2)*MX(4)*HWDRM4(M13SQ,M23SQ,
+     &  M(1),M(3),M(2),M(4),SM(4),SM(2),SW(4),SW(2),A(2),A(4),B(2),B(4))
+        IF(ABS(MX(5)).GT.ZERO) TERM(16)=-MX(2)*MX(5)*HWDRM4(M23SQ,M12SQ,
+     &  M(3),M(2),M(1),M(4),SM(2),SM(5),SW(2),SW(5),A(5),A(2),B(5),B(2))
+        IF(ABS(MX(6)).GT.ZERO) TERM(17)=-MX(2)*MX(6)*HWDRM4(M23SQ,M12SQ,
+     &  M(3),M(2),M(1),M(4),SM(2),SM(6),SW(2),SW(6),A(6),A(2),B(6),B(2))
+      ENDIF
+      IF(ABS(MX(3)).GT.ZERO.AND.ND.NE.1) THEN
+        TERM(3) = MX(3)**2*HWDRM2(M13SQ,M(1),M(3),M(2),M(4),SM(3),
+     &            SW(3),A(3),B(3))
+        IF(ABS(MX(4)).GT.ZERO) TERM(8)= MX(3)*MX(4)*HWDRM3(M13SQ,M(1),
+     &   M(3),M(2),M(4),SM(3),SM(4),SW(3),SW(4),A(3),A(4),B(3),B(4))
+        IF(ABS(MX(5)).GT.ZERO) TERM(18)=-MX(3)*MX(5)*HWDRM4(M12SQ,M13SQ,
+     &  M(2),M(1),M(3),M(4),SM(5),SM(3),SW(5),SW(3),A(3),A(5),B(3),B(5))
+        IF(ABS(MX(6)).GT.ZERO) TERM(19)=-MX(3)*MX(6)*HWDRM4(M12SQ,M13SQ,
+     &  M(2),M(1),M(3),M(4),SM(6),SM(3),SW(6),SW(3),A(3),A(6),B(3),B(6))
+      ENDIF
+      IF(ABS(MX(4)).GT.ZERO.AND.ND.NE.1) THEN
+        TERM(4) = MX(4)**2*HWDRM2(M13SQ,M(1),M(3),M(2),M(4),SM(4),
+     &            SW(4),A(4),B(4))
+        IF(ABS(MX(5)).GT.ZERO) TERM(20)=-MX(4)*MX(5)*HWDRM4(M12SQ,M13SQ,
+     &  M(2),M(1),M(3),M(4),SM(5),SM(4),SW(5),SW(4),A(4),A(5),B(4),B(5))
+        IF(ABS(MX(6)).GT.ZERO) TERM(21)=-MX(4)*MX(6)*HWDRM4(M12SQ,M13SQ,
+     &  M(2),M(1),M(3),M(4),SM(6),SM(4),SW(6),SW(4),A(4),A(6),B(4),B(6))
+      ENDIF
+      IF(ABS(MX(5)).GT.ZERO.AND.ND.NE.2) THEN
+        TERM(5) = MX(5)**2*HWDRM2(M12SQ,M(1),M(2),M(3),M(4),SM(5),
+     &            SW(5),A(5),B(5))
+        IF(ABS(MX(6)).GT.ZERO) TERM(9)= MX(5)*MX(6)*HWDRM3(M12SQ,M(1),
+     &     M(2),M(3),M(4),SM(5),SM(6),SW(5),SW(6),A(5),A(6),B(5),B(6))
+      ENDIF
+      IF(ABS(MX(6)).GT.ZERO.AND.ND.NE.2) TERM(6) = MX(6)**2*
+     &    HWDRM2(M12SQ,M(1),M(2),M(3),M(4),SM(6),SW(6),A(6),B(6))
+      DO K=10,21
+        TERM(K)=TERM(K)*INFCOL
+      ENDDO
+C--Add them up
+      DO K=1,21
+        HWDRM1 = HWDRM1+TERM(K)
+      ENDDO
+C--Different colour flows for the gluino
+      IF(LM.NE.0) THEN
+        NPLN = 0.0D0
+        PLN = 0.0D0
+        DO K=1,9
+          PLN = PLN+TERM(K)
+        ENDDO
+        DO K=10,21
+          NPLN= NPLN+TERM(K)
+        ENDDO
+        DO K=1,3
+          TEST(K) = (TERM(2*K-1)+TERM(2*K)+TERM(6+K))*(1+NPLN/PLN)
+        ENDDO
+      ELSE
+        DO K=1,3
+          TEST(K) = 0.0D0
+        ENDDO
+      ENDIF
+      IF(TEST(4).LT.ZERO) CALL HWWARN('HWDRM1',50,*999)
+ 999  END
+CDECK  ID>, HWDRM2.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      FUNCTION HWDRM2(X,MA,MB,MC,MD,MR1,GAM1,A,B)
+C-----------------------------------------------------------------------
+C     Function to compute the matrix element squared part of a 3-body
+C     R-parity decay
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION X,MA,MB,MC,MD,A,B,HWDRM2,MR1,GAM1
+      HWDRM2  = (X - MA**2 - MB**2)*(4*A*B*MC*MD +
+     &    (A**2 + B**2)*(-X + MC**2 + MD**2))/
+     &     ((X-MR1**2)**2+GAM1**2*MR1**2)
+      END
+CDECK  ID>, HWDRM3.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      FUNCTION HWDRM3(X,MA,MB,MC,MD,MR1,MR2,GAM1,GAM2,A1,A2,B1,B2)
+C-----------------------------------------------------------------------
+C     Function to compute the light/heavy interference part of a 3-body
+C     R-parity decay
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION X,MA,MB,MC,MD,A1,A2,B1,B2,HWDRM3,MR1,MR2,GAM1
+     &                 ,GAM2
+C
+      HWDRM3  = 2*(X - MA**2 - MB**2)*(2*(A2*B1 + A1*B2)*MC*MD +
+     &    (A1*A2 + B1*B2)*(-X + MC**2 + MD**2))*
+     &  (GAM1*GAM2*MR1*MR2 + (X - MR1**2)*(X - MR2**2))/
+     &  (((X-MR1**2)**2+GAM1**2*MR1**2)*((X-MR2**2)**2+GAM2**2*MR2**2))
+      END
+CDECK  ID>, HWDRM4.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      FUNCTION HWDRM4(X,Y,MA,MB,MC,MD,MR1,MR2,GAM1,GAM2,A1,A2,B1,B2)
+C-----------------------------------------------------------------------
+C     Function to compute the interference part of a 3-body
+C     R-parity decay
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION X,Y,MA,MB,MC,MD,A1,A2,B1,B2,HWDRM4,MR1,MR2,GAM1
+     &                 ,GAM2
+C
+      HWDRM4  = 2*((GAM1*GAM2*MR1*MR2 + (X - MR1**2)*(Y - MR2**2))*
+     &    (A2*B1*MC*MD*(X - MA**2 - MB**2) +
+     &      A1*A2*MA*MC*(X + Y - MA**2 - MC**2) +
+     &      A1*B2*MA*MD*(Y - MB**2 - MC**2) +
+     &      B1*B2*(X*Y - MA**2*MC**2 - MB**2*MD**2)))/
+     &  (((X-MR1**2)**2+GAM1**2*MR1**2)*((Y-MR2**2)**2+GAM2**2*MR2**2))
+      END
+CDECK  ID>, HWDRM5.
+*CMZ :-        -20/07/99  10:56:12  by  Peter Richardson
+*-- Author :    Peter Richardson
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDRM5(X,Y,Z,A,B,MA,MB,MC,MD,MR,GAM)
+C-----------------------------------------------------------------------
+C     Subroutine to find the maximum of the ME
+C-----------------------------------------------------------------------
+      IMPLICIT NONE
+      DOUBLE PRECISION X,Y,Z,MA,MB,MC,MD,MR,GAM,RES(3),A,B,C,D,
+     &                 E2S,E3S,E2M,E3M,LOW,UPP,HWRUNI,EPS,ZERO
+      EXTERNAL HWRUNI
+      PARAMETER(EPS=1D-9,ZERO=0)
+      C = A**2+B**2
+      D = 4*A*B
+      RES(1) = -D*(MA**2 + MB**2)*MC*MD +
+     &          C*(GAM**2*MR**2 + MR**4 - MA**2*MC**2 - MB**2*MC**2 -
+     &          MA**2*MD**2 - MB**2*MD**2)
+      RES(2) = (GAM**2*MR**2 + (-MR**2 + MA**2 + MB**2)**2)*
+     &          (D**2*MC**2*MD**2 +
+     &          2*C*D*MC*MD*(-MR**2 + MC**2 + MD**2) +
+     &          C**2*(GAM**2*MR**2 + (-MR**2 + MC**2 + MD**2)**2))
+      RES(3) = -D*MC*MD+C*(2*MR**2-(MA**2+MB**2+MC**2+MD**2))
+      IF(RES(2).GT.ZERO) THEN
+        RES(2) = SQRT(RES(2))
+      ELSE
+        RES(2) = 0.0D0
+      ENDIF
+      IF((RES(1)+RES(2))/RES(3).GT.(MD-MC)**2.OR.
+     &              (RES(1)+RES(2))/RES(3).LT.(MA+MB)**2) THEN
+        X = (RES(1)-RES(2))/RES(3)
+      ELSE
+        X = (RES(1)+RES(2))/RES(3)
+      ENDIF
+      IF(X.GT.(MD-MC)**2) X = (MD-MC)**2
+      IF(X.LT.(MA+MB)**2) X = (MA+MB)**2
+      E2S = (X-MA**2+MB**2)/(2*SQRT(X))
+      E3S = (MD**2-X-MC**2)/(2*SQRT(X))
+      E2M = E2S**2-MB**2
+      E3M = E3S**2-MC**2
+      IF(E2M.LT.ZERO) THEN
+        IF(ABS(E2M/E2S).GT.EPS) CALL HWWARN('HWDRM5',2,*10)
+ 10     E2M= 0.0D0
+      ENDIF
+      IF(E3M.LT.ZERO) THEN
+        IF(ABS(E3M/E3S).GT.EPS) CALL HWWARN('HWDRM5',3,*20)
+ 20     E3M= 0.0D0
+      ENDIF
+      E2M = SQRT(E2M)
+      E3M = SQRT(E3M)
+      LOW = (E2S+E3S)**2-(E2M+E3M)**2
+      UPP = (E2S+E3S)**2-(E2M-E3M)**2
+      Y   = HWRUNI(1,LOW,UPP)
+      Z   = MA**2+MB**2+MC**2+MD**2-X-Y
+      END
+CDECK  ID>, HWDPWT.
+*CMZ :-        -26/04/91  11.11.55  by  Bryan Webber
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      FUNCTION HWDPWT(EMSQ,A,B,C)
+C-----------------------------------------------------------------------
+C     MATRIX ELEMENT SQUARED FOR PHASE SPACE DECAY
+C-----------------------------------------------------------------------
+      DOUBLE PRECISION HWDPWT,EMSQ,A,B,C
+      HWDPWT=1.
+      END
+CDECK  ID>, HWDTHR.
+*CMZ :-        -26/04/91  14.55.44  by  Federico Carminati
+*-- Author :    Bryan Webber
+C-----------------------------------------------------------------------
+      SUBROUTINE HWDTHR(P0,P1,P2,P3,WEIGHT)
+C-----------------------------------------------------------------------
+C     GENERATES THREE-BODY DECAY 0->1+2+3 DISTRIBUTED
+C     ACCORDING TO PHASE SPACE * WEIGHT
+C-----------------------------------------------------------------------
+      DOUBLE PRECISION HWR,HWRUNI,A,B,C,D,AA,BB,CC,DD,EE,FF,PP,QQ,WW,
+     & RR,PCM1,PC23,WEIGHT,P0(5),P1(5),P2(5),P3(5),P23(5),TWO
+      EXTERNAL HWR,HWRUNI,WEIGHT
+      PARAMETER (TWO=2.D0)
+      A=P0(5)+P1(5)
+      B=P0(5)-P1(5)
+      C=P2(5)+P3(5)
+      IF (B.LT.C) CALL HWWARN('HWDTHR',100,*999)
+      D=ABS(P2(5)-P3(5))
+      AA=A*A
+      BB=B*B
+      CC=C*C
+      DD=D*D
+      EE=(B-C)*(A-D)
+      A=0.5*(AA+BB)
+      B=0.5*(CC+DD)
+      C=4./(A-B)**2
+C
+C  CHOOSE MASS OF SUBSYSTEM 23 WITH PRESCRIBED DISTRIBUTION
+C
+   10 FF=HWRUNI(0,BB,CC)
+      PP=(AA-FF)*(BB-FF)
+      QQ=(CC-FF)*(DD-FF)
+      WW=WEIGHT(FF,A,B,C)**2
+      RR=EE*FF*HWR()
+      IF (PP*QQ*WW.LT.RR*RR) GOTO 10
+C
+C  FF IS MASS SQUARED OF SUBSYSTEM 23.
+C
+C  DO 2-BODY DECAYS 0->1+23, 23->2+3
+C
+      P23(5)=SQRT(FF)
+   &nbs