+++ /dev/null
-
-C*********************************************************************
-
- SUBROUTINE LUSHOW(IP1,IP2,QMAX)
-
-C...Purpose: to generate timelike parton showers from given partons.
- IMPLICIT DOUBLE PRECISION(D)
- COMMON/LUJETS/N,K(4000,5),P(4000,5),V(4000,5)
- COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200)
- COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4)
- SAVE /LUJETS/,/LUDAT1/,/LUDAT2/
- DIMENSION PMTH(5,50),PS(5),PMA(4),PMSD(4),IEP(4),IPA(4),
- &KFLA(4),KFLD(4),KFL(4),ITRY(4),ISI(4),ISL(4),DP(4),DPT(5,4),
- &KSH(0:40),KCII(2),NIIS(2),IIIS(2,2),THEIIS(2,2),PHIIIS(2,2),
- &ISII(2)
-
-C...Initialization of cutoff masses etc.
- IF(MSTJ(41).LE.0.OR.(MSTJ(41).EQ.1.AND.QMAX.LE.PARJ(82)).OR.
- &QMAX.LE.MIN(PARJ(82),PARJ(83))) RETURN
- DO 100 IFL=0,40
- KSH(IFL)=0
- 100 CONTINUE
- KSH(21)=1
- PMTH(1,21)=ULMASS(21)
- PMTH(2,21)=SQRT(PMTH(1,21)**2+0.25*PARJ(82)**2)
- PMTH(3,21)=2.*PMTH(2,21)
- PMTH(4,21)=PMTH(3,21)
- PMTH(5,21)=PMTH(3,21)
- PMTH(1,22)=ULMASS(22)
- PMTH(2,22)=SQRT(PMTH(1,22)**2+0.25*PARJ(83)**2)
- PMTH(3,22)=2.*PMTH(2,22)
- PMTH(4,22)=PMTH(3,22)
- PMTH(5,22)=PMTH(3,22)
- PMQTH1=PARJ(82)
- IF(MSTJ(41).GE.2) PMQTH1=MIN(PARJ(82),PARJ(83))
- PMQTH2=PMTH(2,21)
- IF(MSTJ(41).GE.2) PMQTH2=MIN(PMTH(2,21),PMTH(2,22))
- DO 110 IFL=1,8
- KSH(IFL)=1
- PMTH(1,IFL)=ULMASS(IFL)
- PMTH(2,IFL)=SQRT(PMTH(1,IFL)**2+0.25*PMQTH1**2)
- PMTH(3,IFL)=PMTH(2,IFL)+PMQTH2
- PMTH(4,IFL)=SQRT(PMTH(1,IFL)**2+0.25*PARJ(82)**2)+PMTH(2,21)
- PMTH(5,IFL)=SQRT(PMTH(1,IFL)**2+0.25*PARJ(83)**2)+PMTH(2,22)
- 110 CONTINUE
- DO 120 IFL=11,17,2
- IF(MSTJ(41).GE.2) KSH(IFL)=1
- PMTH(1,IFL)=ULMASS(IFL)
- PMTH(2,IFL)=SQRT(PMTH(1,IFL)**2+0.25*PARJ(83)**2)
- PMTH(3,IFL)=PMTH(2,IFL)+PMTH(2,22)
- PMTH(4,IFL)=PMTH(3,IFL)
- PMTH(5,IFL)=PMTH(3,IFL)
- 120 CONTINUE
- PT2MIN=MAX(0.5*PARJ(82),1.1*PARJ(81))**2
- ALAMS=PARJ(81)**2
- ALFM=LOG(PT2MIN/ALAMS)
-
-C...Store positions of shower initiating partons.
- IF(IP1.GT.0.AND.IP1.LE.MIN(N,MSTU(4)-MSTU(32)).AND.IP2.EQ.0) THEN
- NPA=1
- IPA(1)=IP1
- ELSEIF(MIN(IP1,IP2).GT.0.AND.MAX(IP1,IP2).LE.MIN(N,MSTU(4)-
- &MSTU(32))) THEN
- NPA=2
- IPA(1)=IP1
- IPA(2)=IP2
- ELSEIF(IP1.GT.0.AND.IP1.LE.MIN(N,MSTU(4)-MSTU(32)).AND.IP2.LT.0
- &.AND.IP2.GE.-3) THEN
- NPA=IABS(IP2)
- DO 130 I=1,NPA
- IPA(I)=IP1+I-1
- 130 CONTINUE
- ELSE
- CALL LUERRM(12,
- & '(LUSHOW:) failed to reconstruct showering system')
- IF(MSTU(21).GE.1) RETURN
- ENDIF
-
-C...Check on phase space available for emission.
- IREJ=0
- DO 140 J=1,5
- PS(J)=0.
- 140 CONTINUE
- PM=0.
- DO 160 I=1,NPA
- KFLA(I)=IABS(K(IPA(I),2))
- PMA(I)=P(IPA(I),5)
-C...Special cutoff masses for t, l, h with variable masses.
- IFLA=KFLA(I)
- IF(KFLA(I).GE.6.AND.KFLA(I).LE.8) THEN
- IFLA=37+KFLA(I)+ISIGN(2,K(IPA(I),2))
- PMTH(1,IFLA)=PMA(I)
- PMTH(2,IFLA)=SQRT(PMTH(1,IFLA)**2+0.25*PMQTH1**2)
- PMTH(3,IFLA)=PMTH(2,IFLA)+PMQTH2
- PMTH(4,IFLA)=SQRT(PMTH(1,IFLA)**2+0.25*PARJ(82)**2)+PMTH(2,21)
- PMTH(5,IFLA)=SQRT(PMTH(1,IFLA)**2+0.25*PARJ(83)**2)+PMTH(2,22)
- ENDIF
- IF(KFLA(I).LE.40) THEN
- IF(KSH(KFLA(I)).EQ.1) PMA(I)=PMTH(3,IFLA)
- ENDIF
- PM=PM+PMA(I)
- IF(KFLA(I).GT.40) THEN
- IREJ=IREJ+1
- ELSE
- IF(KSH(KFLA(I)).EQ.0.OR.PMA(I).GT.QMAX) IREJ=IREJ+1
- ENDIF
- DO 150 J=1,4
- PS(J)=PS(J)+P(IPA(I),J)
- 150 CONTINUE
- 160 CONTINUE
- IF(IREJ.EQ.NPA) RETURN
- PS(5)=SQRT(MAX(0.,PS(4)**2-PS(1)**2-PS(2)**2-PS(3)**2))
- IF(NPA.EQ.1) PS(5)=PS(4)
- IF(PS(5).LE.PM+PMQTH1) RETURN
-
-C...Check if 3-jet matrix elements to be used.
- M3JC=0
- IF(NPA.EQ.2.AND.MSTJ(47).GE.1) THEN
- IF(KFLA(1).GE.1.AND.KFLA(1).LE.8.AND.KFLA(2).GE.1.AND.
- & KFLA(2).LE.8) M3JC=1
- IF((KFLA(1).EQ.11.OR.KFLA(1).EQ.13.OR.KFLA(1).EQ.15.OR.
- & KFLA(1).EQ.17).AND.KFLA(2).EQ.KFLA(1)) M3JC=1
- IF((KFLA(1).EQ.11.OR.KFLA(1).EQ.13.OR.KFLA(1).EQ.15.OR.
- & KFLA(1).EQ.17).AND.KFLA(2).EQ.KFLA(1)+1) M3JC=1
- IF((KFLA(1).EQ.12.OR.KFLA(1).EQ.14.OR.KFLA(1).EQ.16.OR.
- & KFLA(1).EQ.18).AND.KFLA(2).EQ.KFLA(1)-1) M3JC=1
- IF(MSTJ(47).EQ.2.OR.MSTJ(47).EQ.4) M3JC=1
- M3JCM=0
- IF(M3JC.EQ.1.AND.MSTJ(47).GE.3.AND.KFLA(1).EQ.KFLA(2)) THEN
- M3JCM=1
- QME=(2.*PMTH(1,KFLA(1))/PS(5))**2
- ENDIF
- ENDIF
-
-C...Find if interference with initial state partons.
- MIIS=0
- IF(MSTJ(50).GE.1.AND.MSTJ(50).LE.3.AND.NPA.EQ.2) MIIS=MSTJ(50)
- IF(MIIS.NE.0) THEN
- DO 180 I=1,2
- KCII(I)=0
- KCA=LUCOMP(KFLA(I))
- IF(KCA.NE.0) KCII(I)=KCHG(KCA,2)*ISIGN(1,K(IPA(I),2))
- NIIS(I)=0
- IF(KCII(I).NE.0) THEN
- DO 170 J=1,2
- ICSI=MOD(K(IPA(I),3+J)/MSTU(5),MSTU(5))
- IF(ICSI.GT.0.AND.ICSI.NE.IPA(1).AND.ICSI.NE.IPA(2).AND.
- & (KCII(I).EQ.(-1)**(J+1).OR.KCII(I).EQ.2)) THEN
- NIIS(I)=NIIS(I)+1
- IIIS(I,NIIS(I))=ICSI
- ENDIF
- 170 CONTINUE
- ENDIF
- 180 CONTINUE
- IF(NIIS(1)+NIIS(2).EQ.0) MIIS=0
- ENDIF
-
-C...Boost interfering initial partons to rest frame
-C...and reconstruct their polar and azimuthal angles.
- IF(MIIS.NE.0) THEN
- DO 200 I=1,2
- DO 190 J=1,5
- K(N+I,J)=K(IPA(I),J)
- P(N+I,J)=P(IPA(I),J)
- V(N+I,J)=0.
- 190 CONTINUE
- 200 CONTINUE
- DO 220 I=3,2+NIIS(1)
- DO 210 J=1,5
- K(N+I,J)=K(IIIS(1,I-2),J)
- P(N+I,J)=P(IIIS(1,I-2),J)
- V(N+I,J)=0.
- 210 CONTINUE
- 220 CONTINUE
- DO 240 I=3+NIIS(1),2+NIIS(1)+NIIS(2)
- DO 230 J=1,5
- K(N+I,J)=K(IIIS(2,I-2-NIIS(1)),J)
- P(N+I,J)=P(IIIS(2,I-2-NIIS(1)),J)
- V(N+I,J)=0.
- 230 CONTINUE
- 240 CONTINUE
- CALL LUDBRB(N+1,N+2+NIIS(1)+NIIS(2),0.,0.,-DBLE(PS(1)/PS(4)),
- & -DBLE(PS(2)/PS(4)),-DBLE(PS(3)/PS(4)))
- PHI=ULANGL(P(N+1,1),P(N+1,2))
- CALL LUDBRB(N+1,N+2+NIIS(1)+NIIS(2),0.,-PHI,0D0,0D0,0D0)
- THE=ULANGL(P(N+1,3),P(N+1,1))
- CALL LUDBRB(N+1,N+2+NIIS(1)+NIIS(2),-THE,0.,0D0,0D0,0D0)
- DO 250 I=3,2+NIIS(1)
- THEIIS(1,I-2)=ULANGL(P(N+I,3),SQRT(P(N+I,1)**2+P(N+I,2)**2))
- PHIIIS(1,I-2)=ULANGL(P(N+I,1),P(N+I,2))
- 250 CONTINUE
- DO 260 I=3+NIIS(1),2+NIIS(1)+NIIS(2)
- THEIIS(2,I-2-NIIS(1))=PARU(1)-ULANGL(P(N+I,3),
- & SQRT(P(N+I,1)**2+P(N+I,2)**2))
- PHIIIS(2,I-2-NIIS(1))=ULANGL(P(N+I,1),P(N+I,2))
- 260 CONTINUE
- ENDIF
-
-C...Define imagined single initiator of shower for parton system.
- NS=N
- IF(N.GT.MSTU(4)-MSTU(32)-5) THEN
- CALL LUERRM(11,'(LUSHOW:) no more memory left in LUJETS')
- IF(MSTU(21).GE.1) RETURN
- ENDIF
- IF(NPA.GE.2) THEN
- K(N+1,1)=11
- K(N+1,2)=21
- K(N+1,3)=0
- K(N+1,4)=0
- K(N+1,5)=0
- P(N+1,1)=0.
- P(N+1,2)=0.
- P(N+1,3)=0.
- P(N+1,4)=PS(5)
- P(N+1,5)=PS(5)
- V(N+1,5)=PS(5)**2
- N=N+1
- ENDIF
-
-C...Loop over partons that may branch.
- NEP=NPA
- IM=NS
- IF(NPA.EQ.1) IM=NS-1
- 270 IM=IM+1
- IF(N.GT.NS) THEN
- IF(IM.GT.N) GOTO 510
- KFLM=IABS(K(IM,2))
- IF(KFLM.GT.40) GOTO 270
- IF(KSH(KFLM).EQ.0) GOTO 270
- IFLM=KFLM
- IF(KFLM.GE.6.AND.KFLM.LE.8) IFLM=37+KFLM+ISIGN(2,K(IM,2))
- IF(P(IM,5).LT.PMTH(2,IFLM)) GOTO 270
- IGM=K(IM,3)
- ELSE
- IGM=-1
- ENDIF
- IF(N+NEP.GT.MSTU(4)-MSTU(32)-5) THEN
- CALL LUERRM(11,'(LUSHOW:) no more memory left in LUJETS')
- IF(MSTU(21).GE.1) RETURN
- ENDIF
-
-C...Position of aunt (sister to branching parton).
-C...Origin and flavour of daughters.
- IAU=0
- IF(IGM.GT.0) THEN
- IF(K(IM-1,3).EQ.IGM) IAU=IM-1
- IF(N.GE.IM+1.AND.K(IM+1,3).EQ.IGM) IAU=IM+1
- ENDIF
- IF(IGM.GE.0) THEN
- K(IM,4)=N+1
- DO 280 I=1,NEP
- K(N+I,3)=IM
- 280 CONTINUE
- ELSE
- K(N+1,3)=IPA(1)
- ENDIF
- IF(IGM.LE.0) THEN
- DO 290 I=1,NEP
- K(N+I,2)=K(IPA(I),2)
- 290 CONTINUE
- ELSEIF(KFLM.NE.21) THEN
- K(N+1,2)=K(IM,2)
- K(N+2,2)=K(IM,5)
- ELSEIF(K(IM,5).EQ.21) THEN
- K(N+1,2)=21
- K(N+2,2)=21
- ELSE
- K(N+1,2)=K(IM,5)
- K(N+2,2)=-K(IM,5)
- ENDIF
-
-C...Reset flags on daughers and tries made.
- DO 300 IP=1,NEP
- K(N+IP,1)=3
- K(N+IP,4)=0
- K(N+IP,5)=0
- KFLD(IP)=IABS(K(N+IP,2))
- IF(KCHG(LUCOMP(KFLD(IP)),2).EQ.0) K(N+IP,1)=1
- ITRY(IP)=0
- ISL(IP)=0
- ISI(IP)=0
- IF(KFLD(IP).LE.40) THEN
- IF(KSH(KFLD(IP)).EQ.1) ISI(IP)=1
- ENDIF
- 300 CONTINUE
- ISLM=0
-
-C...Maximum virtuality of daughters.
- IF(IGM.LE.0) THEN
- DO 310 I=1,NPA
- IF(NPA.GE.3) P(N+I,4)=(PS(4)*P(IPA(I),4)-PS(1)*P(IPA(I),1)-
- & PS(2)*P(IPA(I),2)-PS(3)*P(IPA(I),3))/PS(5)
- P(N+I,5)=MIN(QMAX,PS(5))
- IF(NPA.GE.3) P(N+I,5)=MIN(P(N+I,5),P(N+I,4))
- IF(ISI(I).EQ.0) P(N+I,5)=P(IPA(I),5)
- 310 CONTINUE
- ELSE
- IF(MSTJ(43).LE.2) PEM=V(IM,2)
- IF(MSTJ(43).GE.3) PEM=P(IM,4)
- P(N+1,5)=MIN(P(IM,5),V(IM,1)*PEM)
- P(N+2,5)=MIN(P(IM,5),(1.-V(IM,1))*PEM)
- IF(K(N+2,2).EQ.22) P(N+2,5)=PMTH(1,22)
- ENDIF
- DO 320 I=1,NEP
- PMSD(I)=P(N+I,5)
- IF(ISI(I).EQ.1) THEN
- IFLD=KFLD(I)
- IF(KFLD(I).GE.6.AND.KFLD(I).LE.8) IFLD=37+KFLD(I)+
- & ISIGN(2,K(N+I,2))
- IF(P(N+I,5).LE.PMTH(3,IFLD)) P(N+I,5)=PMTH(1,IFLD)
- ENDIF
- V(N+I,5)=P(N+I,5)**2
- 320 CONTINUE
-
-C...Choose one of the daughters for evolution.
- 330 INUM=0
- IF(NEP.EQ.1) INUM=1
- DO 340 I=1,NEP
- IF(INUM.EQ.0.AND.ISL(I).EQ.1) INUM=I
- 340 CONTINUE
- DO 350 I=1,NEP
- IF(INUM.EQ.0.AND.ITRY(I).EQ.0.AND.ISI(I).EQ.1) THEN
- IFLD=KFLD(I)
- IF(KFLD(I).GE.6.AND.KFLD(I).LE.8) IFLD=37+KFLD(I)+
- & ISIGN(2,K(N+I,2))
- IF(P(N+I,5).GE.PMTH(2,IFLD)) INUM=I
- ENDIF
- 350 CONTINUE
- IF(INUM.EQ.0) THEN
- RMAX=0.
- DO 360 I=1,NEP
- IF(ISI(I).EQ.1.AND.PMSD(I).GE.PMQTH2) THEN
- RPM=P(N+I,5)/PMSD(I)
- IFLD=KFLD(I)
- IF(KFLD(I).GE.6.AND.KFLD(I).LE.8) IFLD=37+KFLD(I)+
- & ISIGN(2,K(N+I,2))
- IF(RPM.GT.RMAX.AND.P(N+I,5).GE.PMTH(2,IFLD)) THEN
- RMAX=RPM
- INUM=I
- ENDIF
- ENDIF
- 360 CONTINUE
- ENDIF
-
-C...Store information on choice of evolving daughter.
- INUM=MAX(1,INUM)
- IEP(1)=N+INUM
- DO 370 I=2,NEP
- IEP(I)=IEP(I-1)+1
- IF(IEP(I).GT.N+NEP) IEP(I)=N+1
- 370 CONTINUE
- DO 380 I=1,NEP
- KFL(I)=IABS(K(IEP(I),2))
- 380 CONTINUE
- ITRY(INUM)=ITRY(INUM)+1
- IF(ITRY(INUM).GT.200) THEN
- CALL LUERRM(14,'(LUSHOW:) caught in infinite loop')
- IF(MSTU(21).GE.1) RETURN
- ENDIF
- Z=0.5
- IF(KFL(1).GT.40) GOTO 430
- IF(KSH(KFL(1)).EQ.0) GOTO 430
- IFL=KFL(1)
- IF(KFL(1).GE.6.AND.KFL(1).LE.8) IFL=37+KFL(1)+
- &ISIGN(2,K(IEP(1),2))
- IF(P(IEP(1),5).LT.PMTH(2,IFL)) GOTO 430
-
-C...Select side for interference with initial state partons.
- IF(MIIS.GE.1.AND.IEP(1).LE.NS+3) THEN
- III=IEP(1)-NS-1
- ISII(III)=0
- IF(IABS(KCII(III)).EQ.1.AND.NIIS(III).EQ.1) THEN
- ISII(III)=1
- ELSEIF(KCII(III).EQ.2.AND.NIIS(III).EQ.1) THEN
- IF(RLU(0).GT.0.5) ISII(III)=1
- ELSEIF(KCII(III).EQ.2.AND.NIIS(III).EQ.2) THEN
- ISII(III)=1
- IF(RLU(0).GT.0.5) ISII(III)=2
- ENDIF
- ENDIF
-
-C...Calculate allowed z range.
- IF(NEP.EQ.1) THEN
- PMED=PS(4)
- ELSEIF(IGM.EQ.0.OR.MSTJ(43).LE.2) THEN
- PMED=P(IM,5)
- ELSE
- IF(INUM.EQ.1) PMED=V(IM,1)*PEM
- IF(INUM.EQ.2) PMED=(1.-V(IM,1))*PEM
- ENDIF
- IF(MOD(MSTJ(43),2).EQ.1) THEN
- ZC=PMTH(2,21)/PMED
- ZCE=PMTH(2,22)/PMED
- ELSE
- ZC=0.5*(1.-SQRT(MAX(0.,1.-(2.*PMTH(2,21)/PMED)**2)))
- IF(ZC.LT.1E-4) ZC=(PMTH(2,21)/PMED)**2
- ZCE=0.5*(1.-SQRT(MAX(0.,1.-(2.*PMTH(2,22)/PMED)**2)))
- IF(ZCE.LT.1E-4) ZCE=(PMTH(2,22)/PMED)**2
- ENDIF
- ZC=MIN(ZC,0.491)
- ZCE=MIN(ZCE,0.491)
- IF((MSTJ(41).EQ.1.AND.ZC.GT.0.49).OR.(MSTJ(41).GE.2.AND.
- &MIN(ZC,ZCE).GT.0.49)) THEN
- P(IEP(1),5)=PMTH(1,IFL)
- V(IEP(1),5)=P(IEP(1),5)**2
- GOTO 430
- ENDIF
-
-C...Integral of Altarelli-Parisi z kernel for QCD.
- IF(MSTJ(49).EQ.0.AND.KFL(1).EQ.21) THEN
- FBR=6.*LOG((1.-ZC)/ZC)+MSTJ(45)*(0.5-ZC)
- ELSEIF(MSTJ(49).EQ.0) THEN
- FBR=(8./3.)*LOG((1.-ZC)/ZC)
-
-C...Integral of Altarelli-Parisi z kernel for scalar gluon.
- ELSEIF(MSTJ(49).EQ.1.AND.KFL(1).EQ.21) THEN
- FBR=(PARJ(87)+MSTJ(45)*PARJ(88))*(1.-2.*ZC)
- ELSEIF(MSTJ(49).EQ.1) THEN
- FBR=(1.-2.*ZC)/3.
- IF(IGM.EQ.0.AND.M3JC.EQ.1) FBR=4.*FBR
-
-C...Integral of Altarelli-Parisi z kernel for Abelian vector gluon.
- ELSEIF(KFL(1).EQ.21) THEN
- FBR=6.*MSTJ(45)*(0.5-ZC)
- ELSE
- FBR=2.*LOG((1.-ZC)/ZC)
- ENDIF
-
-C...Reset QCD probability for lepton.
- IF(KFL(1).GE.11.AND.KFL(1).LE.18) FBR=0.
-
-C...Integral of Altarelli-Parisi kernel for photon emission.
- IF(MSTJ(41).GE.2.AND.KFL(1).GE.1.AND.KFL(1).LE.18) THEN
- FBRE=(KCHG(KFL(1),1)/3.)**2*2.*LOG((1.-ZCE)/ZCE)
- IF(MSTJ(41).EQ.10) FBRE=PARJ(84)*FBRE
- ENDIF
-
-C...Inner veto algorithm starts. Find maximum mass for evolution.
- 390 PMS=V(IEP(1),5)
- IF(IGM.GE.0) THEN
- PM2=0.
- DO 400 I=2,NEP
- PM=P(IEP(I),5)
- IF(KFL(I).LE.40) THEN
- IFLI=KFL(I)
- IF(KFL(I).GE.6.AND.KFL(I).LE.8) IFLI=37+KFL(I)+
- & ISIGN(2,K(IEP(I),2))
- IF(KSH(KFL(I)).EQ.1) PM=PMTH(2,IFLI)
- ENDIF
- PM2=PM2+PM
- 400 CONTINUE
- PMS=MIN(PMS,(P(IM,5)-PM2)**2)
- ENDIF
-
-C...Select mass for daughter in QCD evolution.
- B0=27./6.
- DO 410 IFF=4,MSTJ(45)
- IF(PMS.GT.4.*PMTH(2,IFF)**2) B0=(33.-2.*IFF)/6.
- 410 CONTINUE
- IF(FBR.LT.1E-3) THEN
- PMSQCD=0.
- ELSEIF(MSTJ(44).LE.0) THEN
- PMSQCD=PMS*EXP(MAX(-50.,LOG(RLU(0))*PARU(2)/(PARU(111)*FBR)))
- ELSEIF(MSTJ(44).EQ.1) THEN
- PMSQCD=4.*ALAMS*(0.25*PMS/ALAMS)**(RLU(0)**(B0/FBR))
- ELSE
- PMSQCD=PMS*EXP(MAX(-50.,ALFM*B0*LOG(RLU(0))/FBR))
- ENDIF
- IF(ZC.GT.0.49.OR.PMSQCD.LE.PMTH(4,IFL)**2) PMSQCD=PMTH(2,IFL)**2
- V(IEP(1),5)=PMSQCD
- MCE=1
-
-C...Select mass for daughter in QED evolution.
- IF(MSTJ(41).GE.2.AND.KFL(1).GE.1.AND.KFL(1).LE.18) THEN
- PMSQED=PMS*EXP(MAX(-50.,LOG(RLU(0))*PARU(2)/(PARU(101)*FBRE)))
- IF(ZCE.GT.0.49.OR.PMSQED.LE.PMTH(5,IFL)**2) PMSQED=
- & PMTH(2,IFL)**2
- IF(PMSQED.GT.PMSQCD) THEN
- V(IEP(1),5)=PMSQED
- MCE=2
- ENDIF
- ENDIF
-
-C...Check whether daughter mass below cutoff.
- P(IEP(1),5)=SQRT(V(IEP(1),5))
- IF(P(IEP(1),5).LE.PMTH(3,IFL)) THEN
- P(IEP(1),5)=PMTH(1,IFL)
- V(IEP(1),5)=P(IEP(1),5)**2
- GOTO 430
- ENDIF
-
-C...Select z value of branching: q -> qgamma.
- IF(MCE.EQ.2) THEN
- Z=1.-(1.-ZCE)*(ZCE/(1.-ZCE))**RLU(0)
- IF(1.+Z**2.LT.2.*RLU(0)) GOTO 390
- K(IEP(1),5)=22
-
-C...Select z value of branching: q -> qg, g -> gg, g -> qqbar.
- ELSEIF(MSTJ(49).NE.1.AND.KFL(1).NE.21) THEN
- Z=1.-(1.-ZC)*(ZC/(1.-ZC))**RLU(0)
- IF(1.+Z**2.LT.2.*RLU(0)) GOTO 390
- K(IEP(1),5)=21
- ELSEIF(MSTJ(49).EQ.0.AND.MSTJ(45)*(0.5-ZC).LT.RLU(0)*FBR) THEN
- Z=(1.-ZC)*(ZC/(1.-ZC))**RLU(0)
- IF(RLU(0).GT.0.5) Z=1.-Z
- IF((1.-Z*(1.-Z))**2.LT.RLU(0)) GOTO 390
- K(IEP(1),5)=21
- ELSEIF(MSTJ(49).NE.1) THEN
- Z=ZC+(1.-2.*ZC)*RLU(0)
- IF(Z**2+(1.-Z)**2.LT.RLU(0)) GOTO 390
- KFLB=1+INT(MSTJ(45)*RLU(0))
- PMQ=4.*PMTH(2,KFLB)**2/V(IEP(1),5)
- IF(PMQ.GE.1.) GOTO 390
- PMQ0=4.*PMTH(2,21)**2/V(IEP(1),5)
- IF(MOD(MSTJ(43),2).EQ.0.AND.(1.+0.5*PMQ)*SQRT(1.-PMQ).LT.
- & RLU(0)*(1.+0.5*PMQ0)*SQRT(1.-PMQ0)) GOTO 390
- K(IEP(1),5)=KFLB
-
-C...Ditto for scalar gluon model.
- ELSEIF(KFL(1).NE.21) THEN
- Z=1.-SQRT(ZC**2+RLU(0)*(1.-2.*ZC))
- K(IEP(1),5)=21
- ELSEIF(RLU(0)*(PARJ(87)+MSTJ(45)*PARJ(88)).LE.PARJ(87)) THEN
- Z=ZC+(1.-2.*ZC)*RLU(0)
- K(IEP(1),5)=21
- ELSE
- Z=ZC+(1.-2.*ZC)*RLU(0)
- KFLB=1+INT(MSTJ(45)*RLU(0))
- PMQ=4.*PMTH(2,KFLB)**2/V(IEP(1),5)
- IF(PMQ.GE.1.) GOTO 390
- K(IEP(1),5)=KFLB
- ENDIF
- IF(MCE.EQ.1.AND.MSTJ(44).GE.2) THEN
- IF(Z*(1.-Z)*V(IEP(1),5).LT.PT2MIN) GOTO 390
- IF(ALFM/LOG(V(IEP(1),5)*Z*(1.-Z)/ALAMS).LT.RLU(0)) GOTO 390
- ENDIF
-
-C...Check if z consistent with chosen m.
- IF(KFL(1).EQ.21) THEN
- KFLGD1=IABS(K(IEP(1),5))
- KFLGD2=KFLGD1
- ELSE
- KFLGD1=KFL(1)
- KFLGD2=IABS(K(IEP(1),5))
- ENDIF
- IF(NEP.EQ.1) THEN
- PED=PS(4)
- ELSEIF(NEP.GE.3) THEN
- PED=P(IEP(1),4)
- ELSEIF(IGM.EQ.0.OR.MSTJ(43).LE.2) THEN
- PED=0.5*(V(IM,5)+V(IEP(1),5)-PM2**2)/P(IM,5)
- ELSE
- IF(IEP(1).EQ.N+1) PED=V(IM,1)*PEM
- IF(IEP(1).EQ.N+2) PED=(1.-V(IM,1))*PEM
- ENDIF
- IF(MOD(MSTJ(43),2).EQ.1) THEN
- IFLGD1=KFLGD1
- IF(KFLGD1.GE.6.AND.KFLGD1.LE.8) IFLGD1=IFL
- PMQTH3=0.5*PARJ(82)
- IF(KFLGD2.EQ.22) PMQTH3=0.5*PARJ(83)
- PMQ1=(PMTH(1,IFLGD1)**2+PMQTH3**2)/V(IEP(1),5)
- PMQ2=(PMTH(1,KFLGD2)**2+PMQTH3**2)/V(IEP(1),5)
- ZD=SQRT(MAX(0.,(1.-V(IEP(1),5)/PED**2)*((1.-PMQ1-PMQ2)**2-
- & 4.*PMQ1*PMQ2)))
- ZH=1.+PMQ1-PMQ2
- ELSE
- ZD=SQRT(MAX(0.,1.-V(IEP(1),5)/PED**2))
- ZH=1.
- ENDIF
- ZL=0.5*(ZH-ZD)
- ZU=0.5*(ZH+ZD)
- IF(Z.LT.ZL.OR.Z.GT.ZU) GOTO 390
- IF(KFL(1).EQ.21) V(IEP(1),3)=LOG(ZU*(1.-ZL)/MAX(1E-20,ZL*
- &(1.-ZU)))
- IF(KFL(1).NE.21) V(IEP(1),3)=LOG((1.-ZL)/MAX(1E-10,1.-ZU))
-
-C...Width suppression for q -> q + g.
- IF(MSTJ(40).NE.0.AND.KFL(1).NE.21) THEN
- IF(IGM.EQ.0) THEN
- EGLU=0.5*PS(5)*(1.-Z)*(1.+V(IEP(1),5)/V(NS+1,5))
- ELSE
- EGLU=PMED*(1.-Z)
- ENDIF
- CHI=PARJ(89)**2/(PARJ(89)**2+EGLU**2)
- IF(MSTJ(40).EQ.1) THEN
- IF(CHI.LT.RLU(0)) GOTO 390
- ELSEIF(MSTJ(40).EQ.2) THEN
- IF(1.-CHI.LT.RLU(0)) GOTO 390
- ENDIF
- ENDIF
-
-C...Three-jet matrix element correction.
- IF(IGM.EQ.0.AND.M3JC.EQ.1) THEN
- X1=Z*(1.+V(IEP(1),5)/V(NS+1,5))
- X2=1.-V(IEP(1),5)/V(NS+1,5)
- X3=(1.-X1)+(1.-X2)
- IF(MCE.EQ.2) THEN
- KI1=K(IPA(INUM),2)
- KI2=K(IPA(3-INUM),2)
- QF1=KCHG(IABS(KI1),1)*ISIGN(1,KI1)/3.
- QF2=KCHG(IABS(KI2),1)*ISIGN(1,KI2)/3.
- WSHOW=QF1**2*(1.-X1)/X3*(1.+(X1/(2.-X2))**2)+
- & QF2**2*(1.-X2)/X3*(1.+(X2/(2.-X1))**2)
- WME=(QF1*(1.-X1)/X3-QF2*(1.-X2)/X3)**2*(X1**2+X2**2)
- ELSEIF(MSTJ(49).NE.1) THEN
- WSHOW=1.+(1.-X1)/X3*(X1/(2.-X2))**2+
- & (1.-X2)/X3*(X2/(2.-X1))**2
- WME=X1**2+X2**2
- IF(M3JCM.EQ.1) WME=WME-QME*X3-0.5*QME**2-
- & (0.5*QME+0.25*QME**2)*((1.-X2)/MAX(1E-7,1.-X1)+
- & (1.-X1)/MAX(1E-7,1.-X2))
- ELSE
- WSHOW=4.*X3*((1.-X1)/(2.-X2)**2+(1.-X2)/(2.-X1)**2)
- WME=X3**2
- IF(MSTJ(102).GE.2) WME=X3**2-2.*(1.+X3)*(1.-X1)*(1.-X2)*
- & PARJ(171)
- ENDIF
- IF(WME.LT.RLU(0)*WSHOW) GOTO 390
-
-C...Impose angular ordering by rejection of nonordered emission.
- ELSEIF(MCE.EQ.1.AND.IGM.GT.0.AND.MSTJ(42).GE.2) THEN
- MAOM=1
- ZM=V(IM,1)
- IF(IEP(1).EQ.N+2) ZM=1.-V(IM,1)
- THE2ID=Z*(1.-Z)*(ZM*P(IM,4))**2/V(IEP(1),5)
- IAOM=IM
- 420 IF(K(IAOM,5).EQ.22) THEN
- IAOM=K(IAOM,3)
- IF(K(IAOM,3).LE.NS) MAOM=0
- IF(MAOM.EQ.1) GOTO 420
- ENDIF
- IF(MAOM.EQ.1) THEN
- THE2IM=V(IAOM,1)*(1.-V(IAOM,1))*P(IAOM,4)**2/V(IAOM,5)
- IF(THE2ID.LT.THE2IM) GOTO 390
- ENDIF
- ENDIF
-
-C...Impose user-defined maximum angle at first branching.
- IF(MSTJ(48).EQ.1) THEN
- IF(NEP.EQ.1.AND.IM.EQ.NS) THEN
- THE2ID=Z*(1.-Z)*PS(4)**2/V(IEP(1),5)
- IF(THE2ID.LT.1./PARJ(85)**2) GOTO 390
- ELSEIF(NEP.EQ.2.AND.IEP(1).EQ.NS+2) THEN
- THE2ID=Z*(1.-Z)*(0.5*P(IM,4))**2/V(IEP(1),5)
- IF(THE2ID.LT.1./PARJ(85)**2) GOTO 390
- ELSEIF(NEP.EQ.2.AND.IEP(1).EQ.NS+3) THEN
- THE2ID=Z*(1.-Z)*(0.5*P(IM,4))**2/V(IEP(1),5)
- IF(THE2ID.LT.1./PARJ(86)**2) GOTO 390
- ENDIF
- ENDIF
-
-C...Impose angular constraint in first branching from interference
-C...with initial state partons.
- IF(MIIS.GE.2.AND.IEP(1).LE.NS+3) THEN
- THE2D=MAX((1.-Z)/Z,Z/(1.-Z))*V(IEP(1),5)/(0.5*P(IM,4))**2
- IF(IEP(1).EQ.NS+2.AND.ISII(1).GE.1) THEN
- IF(THE2D.GT.THEIIS(1,ISII(1))**2) GOTO 390
- ELSEIF(IEP(1).EQ.NS+3.AND.ISII(2).GE.1) THEN
- IF(THE2D.GT.THEIIS(2,ISII(2))**2) GOTO 390
- ENDIF
- ENDIF
-
-C...End of inner veto algorithm. Check if only one leg evolved so far.
- 430 V(IEP(1),1)=Z
- ISL(1)=0
- ISL(2)=0
- IF(NEP.EQ.1) GOTO 460
- IF(NEP.EQ.2.AND.P(IEP(1),5)+P(IEP(2),5).GE.P(IM,5)) GOTO 330
- DO 440 I=1,NEP
- IF(ITRY(I).EQ.0.AND.KFLD(I).LE.40) THEN
- IF(KSH(KFLD(I)).EQ.1) THEN
- IFLD=KFLD(I)
- IF(KFLD(I).GE.6.AND.KFLD(I).LE.8) IFLD=37+KFLD(I)+
- & ISIGN(2,K(N+I,2))
- IF(P(N+I,5).GE.PMTH(2,IFLD)) GOTO 330
- ENDIF
- ENDIF
- 440 CONTINUE
-
-C...Check if chosen multiplet m1,m2,z1,z2 is physical.
- IF(NEP.EQ.3) THEN
- PA1S=(P(N+1,4)+P(N+1,5))*(P(N+1,4)-P(N+1,5))
- PA2S=(P(N+2,4)+P(N+2,5))*(P(N+2,4)-P(N+2,5))
- PA3S=(P(N+3,4)+P(N+3,5))*(P(N+3,4)-P(N+3,5))
- PTS=0.25*(2.*PA1S*PA2S+2.*PA1S*PA3S+2.*PA2S*PA3S-
- & PA1S**2-PA2S**2-PA3S**2)/PA1S
- IF(PTS.LE.0.) GOTO 330
- ELSEIF(IGM.EQ.0.OR.MSTJ(43).LE.2.OR.MOD(MSTJ(43),2).EQ.0) THEN
- DO 450 I1=N+1,N+2
- KFLDA=IABS(K(I1,2))
- IF(KFLDA.GT.40) GOTO 450
- IF(KSH(KFLDA).EQ.0) GOTO 450
- IFLDA=KFLDA
- IF(KFLDA.GE.6.AND.KFLDA.LE.8) IFLDA=37+KFLDA+
- & ISIGN(2,K(I1,2))
- IF(P(I1,5).LT.PMTH(2,IFLDA)) GOTO 450
- IF(KFLDA.EQ.21) THEN
- KFLGD1=IABS(K(I1,5))
- KFLGD2=KFLGD1
- ELSE
- KFLGD1=KFLDA
- KFLGD2=IABS(K(I1,5))
- ENDIF
- I2=2*N+3-I1
- IF(IGM.EQ.0.OR.MSTJ(43).LE.2) THEN
- PED=0.5*(V(IM,5)+V(I1,5)-V(I2,5))/P(IM,5)
- ELSE
- IF(I1.EQ.N+1) ZM=V(IM,1)
- IF(I1.EQ.N+2) ZM=1.-V(IM,1)
- PML=SQRT((V(IM,5)-V(N+1,5)-V(N+2,5))**2-
- & 4.*V(N+1,5)*V(N+2,5))
- PED=PEM*(0.5*(V(IM,5)-PML+V(I1,5)-V(I2,5))+PML*ZM)/V(IM,5)
- ENDIF
- IF(MOD(MSTJ(43),2).EQ.1) THEN
- PMQTH3=0.5*PARJ(82)
- IF(KFLGD2.EQ.22) PMQTH3=0.5*PARJ(83)
- IFLGD1=KFLGD1
- IF(KFLGD1.GE.6.AND.KFLGD1.LE.8) IFLGD1=IFLDA
- PMQ1=(PMTH(1,IFLGD1)**2+PMQTH3**2)/V(I1,5)
- PMQ2=(PMTH(1,KFLGD2)**2+PMQTH3**2)/V(I1,5)
- ZD=SQRT(MAX(0.,(1.-V(I1,5)/PED**2)*((1.-PMQ1-PMQ2)**2-
- & 4.*PMQ1*PMQ2)))
- ZH=1.+PMQ1-PMQ2
- ELSE
- ZD=SQRT(MAX(0.,1.-V(I1,5)/PED**2))
- ZH=1.
- ENDIF
- ZL=0.5*(ZH-ZD)
- ZU=0.5*(ZH+ZD)
- IF(I1.EQ.N+1.AND.(V(I1,1).LT.ZL.OR.V(I1,1).GT.ZU)) ISL(1)=1
- IF(I1.EQ.N+2.AND.(V(I1,1).LT.ZL.OR.V(I1,1).GT.ZU)) ISL(2)=1
- IF(KFLDA.EQ.21) V(I1,4)=LOG(ZU*(1.-ZL)/MAX(1E-20,ZL*(1.-ZU)))
- IF(KFLDA.NE.21) V(I1,4)=LOG((1.-ZL)/MAX(1E-10,1.-ZU))
- 450 CONTINUE
- IF(ISL(1).EQ.1.AND.ISL(2).EQ.1.AND.ISLM.NE.0) THEN
- ISL(3-ISLM)=0
- ISLM=3-ISLM
- ELSEIF(ISL(1).EQ.1.AND.ISL(2).EQ.1) THEN
- ZDR1=MAX(0.,V(N+1,3)/MAX(1E-6,V(N+1,4))-1.)
- ZDR2=MAX(0.,V(N+2,3)/MAX(1E-6,V(N+2,4))-1.)
- IF(ZDR2.GT.RLU(0)*(ZDR1+ZDR2)) ISL(1)=0
- IF(ISL(1).EQ.1) ISL(2)=0
- IF(ISL(1).EQ.0) ISLM=1
- IF(ISL(2).EQ.0) ISLM=2
- ENDIF
- IF(ISL(1).EQ.1.OR.ISL(2).EQ.1) GOTO 330
- ENDIF
- IFLD1=KFLD(1)
- IF(KFLD(1).GE.6.AND.KFLD(1).LE.8) IFLD1=37+KFLD(1)+
- &ISIGN(2,K(N+1,2))
- IFLD2=KFLD(2)
- IF(KFLD(2).GE.6.AND.KFLD(2).LE.8) IFLD2=37+KFLD(2)+
- &ISIGN(2,K(N+2,2))
- IF(IGM.GT.0.AND.MOD(MSTJ(43),2).EQ.1.AND.(P(N+1,5).GE.
- &PMTH(2,IFLD1).OR.P(N+2,5).GE.PMTH(2,IFLD2))) THEN
- PMQ1=V(N+1,5)/V(IM,5)
- PMQ2=V(N+2,5)/V(IM,5)
- ZD=SQRT(MAX(0.,(1.-V(IM,5)/PEM**2)*((1.-PMQ1-PMQ2)**2-
- & 4.*PMQ1*PMQ2)))
- ZH=1.+PMQ1-PMQ2
- ZL=0.5*(ZH-ZD)
- ZU=0.5*(ZH+ZD)
- IF(V(IM,1).LT.ZL.OR.V(IM,1).GT.ZU) GOTO 330
- ENDIF
-
-C...Accepted branch. Construct four-momentum for initial partons.
- 460 MAZIP=0
- MAZIC=0
- IF(NEP.EQ.1) THEN
- P(N+1,1)=0.
- P(N+1,2)=0.
- P(N+1,3)=SQRT(MAX(0.,(P(IPA(1),4)+P(N+1,5))*(P(IPA(1),4)-
- & P(N+1,5))))
- P(N+1,4)=P(IPA(1),4)
- V(N+1,2)=P(N+1,4)
- ELSEIF(IGM.EQ.0.AND.NEP.EQ.2) THEN
- PED1=0.5*(V(IM,5)+V(N+1,5)-V(N+2,5))/P(IM,5)
- P(N+1,1)=0.
- P(N+1,2)=0.
- P(N+1,3)=SQRT(MAX(0.,(PED1+P(N+1,5))*(PED1-P(N+1,5))))
- P(N+1,4)=PED1
- P(N+2,1)=0.
- P(N+2,2)=0.
- P(N+2,3)=-P(N+1,3)
- P(N+2,4)=P(IM,5)-PED1
- V(N+1,2)=P(N+1,4)
- V(N+2,2)=P(N+2,4)
- ELSEIF(NEP.EQ.3) THEN
- P(N+1,1)=0.
- P(N+1,2)=0.
- P(N+1,3)=SQRT(MAX(0.,PA1S))
- P(N+2,1)=SQRT(PTS)
- P(N+2,2)=0.
- P(N+2,3)=0.5*(PA3S-PA2S-PA1S)/P(N+1,3)
- P(N+3,1)=-P(N+2,1)
- P(N+3,2)=0.
- P(N+3,3)=-(P(N+1,3)+P(N+2,3))
- V(N+1,2)=P(N+1,4)
- V(N+2,2)=P(N+2,4)
- V(N+3,2)=P(N+3,4)
-
-C...Construct transverse momentum for ordinary branching in shower.
- ELSE
- ZM=V(IM,1)
- PZM=SQRT(MAX(0.,(PEM+P(IM,5))*(PEM-P(IM,5))))
- PMLS=(V(IM,5)-V(N+1,5)-V(N+2,5))**2-4.*V(N+1,5)*V(N+2,5)
- IF(PZM.LE.0.) THEN
- PTS=0.
- ELSEIF(MOD(MSTJ(43),2).EQ.1) THEN
- PTS=(PEM**2*(ZM*(1.-ZM)*V(IM,5)-(1.-ZM)*V(N+1,5)-
- & ZM*V(N+2,5))-0.25*PMLS)/PZM**2
- ELSE
- PTS=PMLS*(ZM*(1.-ZM)*PEM**2/V(IM,5)-0.25)/PZM**2
- ENDIF
- PT=SQRT(MAX(0.,PTS))
-
-C...Find coefficient of azimuthal asymmetry due to gluon polarization.
- HAZIP=0.
- IF(MSTJ(49).NE.1.AND.MOD(MSTJ(46),2).EQ.1.AND.K(IM,2).EQ.21.
- & AND.IAU.NE.0) THEN
- IF(K(IGM,3).NE.0) MAZIP=1
- ZAU=V(IGM,1)
- IF(IAU.EQ.IM+1) ZAU=1.-V(IGM,1)
- IF(MAZIP.EQ.0) ZAU=0.
- IF(K(IGM,2).NE.21) THEN
- HAZIP=2.*ZAU/(1.+ZAU**2)
- ELSE
- HAZIP=(ZAU/(1.-ZAU*(1.-ZAU)))**2
- ENDIF
- IF(K(N+1,2).NE.21) THEN
- HAZIP=HAZIP*(-2.*ZM*(1.-ZM))/(1.-2.*ZM*(1.-ZM))
- ELSE
- HAZIP=HAZIP*(ZM*(1.-ZM)/(1.-ZM*(1.-ZM)))**2
- ENDIF
- ENDIF
-
-C...Find coefficient of azimuthal asymmetry due to soft gluon
-C...interference.
- HAZIC=0.
- IF(MSTJ(49).NE.2.AND.MSTJ(46).GE.2.AND.(K(N+1,2).EQ.21.OR.
- & K(N+2,2).EQ.21).AND.IAU.NE.0) THEN
- IF(K(IGM,3).NE.0) MAZIC=N+1
- IF(K(IGM,3).NE.0.AND.K(N+1,2).NE.21) MAZIC=N+2
- IF(K(IGM,3).NE.0.AND.K(N+1,2).EQ.21.AND.K(N+2,2).EQ.21.AND.
- & ZM.GT.0.5) MAZIC=N+2
- IF(K(IAU,2).EQ.22) MAZIC=0
- ZS=ZM
- IF(MAZIC.EQ.N+2) ZS=1.-ZM
- ZGM=V(IGM,1)
- IF(IAU.EQ.IM-1) ZGM=1.-V(IGM,1)
- IF(MAZIC.EQ.0) ZGM=1.
- IF(MAZIC.NE.0) HAZIC=(P(IM,5)/P(IGM,5))*
- & SQRT((1.-ZS)*(1.-ZGM)/(ZS*ZGM))
- HAZIC=MIN(0.95,HAZIC)
- ENDIF
- ENDIF
-
-C...Construct kinematics for ordinary branching in shower.
- 470 IF(NEP.EQ.2.AND.IGM.GT.0) THEN
- IF(MOD(MSTJ(43),2).EQ.1) THEN
- P(N+1,4)=PEM*V(IM,1)
- ELSE
- P(N+1,4)=PEM*(0.5*(V(IM,5)-SQRT(PMLS)+V(N+1,5)-V(N+2,5))+
- & SQRT(PMLS)*ZM)/V(IM,5)
- ENDIF
- PHI=PARU(2)*RLU(0)
- P(N+1,1)=PT*COS(PHI)
- P(N+1,2)=PT*SIN(PHI)
- IF(PZM.GT.0.) THEN
- P(N+1,3)=0.5*(V(N+2,5)-V(N+1,5)-V(IM,5)+2.*PEM*P(N+1,4))/PZM
- ELSE
- P(N+1,3)=0.
- ENDIF
- P(N+2,1)=-P(N+1,1)
- P(N+2,2)=-P(N+1,2)
- P(N+2,3)=PZM-P(N+1,3)
- P(N+2,4)=PEM-P(N+1,4)
- IF(MSTJ(43).LE.2) THEN
- V(N+1,2)=(PEM*P(N+1,4)-PZM*P(N+1,3))/P(IM,5)
- V(N+2,2)=(PEM*P(N+2,4)-PZM*P(N+2,3))/P(IM,5)
- ENDIF
- ENDIF
-
-C...Rotate and boost daughters.
- IF(IGM.GT.0) THEN
- IF(MSTJ(43).LE.2) THEN
- BEX=P(IGM,1)/P(IGM,4)
- BEY=P(IGM,2)/P(IGM,4)
- BEZ=P(IGM,3)/P(IGM,4)
- GA=P(IGM,4)/P(IGM,5)
- GABEP=GA*(GA*(BEX*P(IM,1)+BEY*P(IM,2)+BEZ*P(IM,3))/(1.+GA)-
- & P(IM,4))
- ELSE
- BEX=0.
- BEY=0.
- BEZ=0.
- GA=1.
- GABEP=0.
- ENDIF
- THE=ULANGL(P(IM,3)+GABEP*BEZ,SQRT((P(IM,1)+GABEP*BEX)**2+
- & (P(IM,2)+GABEP*BEY)**2))
- PHI=ULANGL(P(IM,1)+GABEP*BEX,P(IM,2)+GABEP*BEY)
- DO 480 I=N+1,N+2
- DP(1)=COS(THE)*COS(PHI)*P(I,1)-SIN(PHI)*P(I,2)+
- & SIN(THE)*COS(PHI)*P(I,3)
- DP(2)=COS(THE)*SIN(PHI)*P(I,1)+COS(PHI)*P(I,2)+
- & SIN(THE)*SIN(PHI)*P(I,3)
- DP(3)=-SIN(THE)*P(I,1)+COS(THE)*P(I,3)
- DP(4)=P(I,4)
- DBP=BEX*DP(1)+BEY*DP(2)+BEZ*DP(3)
- DGABP=GA*(GA*DBP/(1D0+GA)+DP(4))
- P(I,1)=DP(1)+DGABP*BEX
- P(I,2)=DP(2)+DGABP*BEY
- P(I,3)=DP(3)+DGABP*BEZ
- P(I,4)=GA*(DP(4)+DBP)
- 480 CONTINUE
- ENDIF
-
-C...Weight with azimuthal distribution, if required.
- IF(MAZIP.NE.0.OR.MAZIC.NE.0) THEN
- DO 490 J=1,3
- DPT(1,J)=P(IM,J)
- DPT(2,J)=P(IAU,J)
- DPT(3,J)=P(N+1,J)
- 490 CONTINUE
- DPMA=DPT(1,1)*DPT(2,1)+DPT(1,2)*DPT(2,2)+DPT(1,3)*DPT(2,3)
- DPMD=DPT(1,1)*DPT(3,1)+DPT(1,2)*DPT(3,2)+DPT(1,3)*DPT(3,3)
- DPMM=DPT(1,1)**2+DPT(1,2)**2+DPT(1,3)**2
- DO 500 J=1,3
- DPT(4,J)=DPT(2,J)-DPMA*DPT(1,J)/DPMM
- DPT(5,J)=DPT(3,J)-DPMD*DPT(1,J)/DPMM
- 500 CONTINUE
- DPT(4,4)=SQRT(DPT(4,1)**2+DPT(4,2)**2+DPT(4,3)**2)
- DPT(5,4)=SQRT(DPT(5,1)**2+DPT(5,2)**2+DPT(5,3)**2)
- IF(MIN(DPT(4,4),DPT(5,4)).GT.0.1*PARJ(82)) THEN
- CAD=(DPT(4,1)*DPT(5,1)+DPT(4,2)*DPT(5,2)+
- & DPT(4,3)*DPT(5,3))/(DPT(4,4)*DPT(5,4))
- IF(MAZIP.NE.0) THEN
- IF(1.+HAZIP*(2.*CAD**2-1.).LT.RLU(0)*(1.+ABS(HAZIP)))
- & GOTO 470
- ENDIF
- IF(MAZIC.NE.0) THEN
- IF(MAZIC.EQ.N+2) CAD=-CAD
- IF((1.-HAZIC)*(1.-HAZIC*CAD)/(1.+HAZIC**2-2.*HAZIC*CAD)
- & .LT.RLU(0)) GOTO 470
- ENDIF
- ENDIF
- ENDIF
-
-C...Azimuthal anisotropy due to interference with initial state partons.
- IF(MOD(MIIS,2).EQ.1.AND.IGM.EQ.NS+1.AND.(K(N+1,2).EQ.21.OR.
- &K(N+2,2).EQ.21)) THEN
- III=IM-NS-1
- IF(ISII(III).GE.1) THEN
- IAZIID=N+1
- IF(K(N+1,2).NE.21) IAZIID=N+2
- IF(K(N+1,2).EQ.21.AND.K(N+2,2).EQ.21.AND.
- & P(N+1,4).GT.P(N+2,4)) IAZIID=N+2
- THEIID=ULANGL(P(IAZIID,3),SQRT(P(IAZIID,1)**2+P(IAZIID,2)**2))
- IF(III.EQ.2) THEIID=PARU(1)-THEIID
- PHIIID=ULANGL(P(IAZIID,1),P(IAZIID,2))
- HAZII=MIN(0.95,THEIID/THEIIS(III,ISII(III)))
- CAD=COS(PHIIID-PHIIIS(III,ISII(III)))
- PHIREL=ABS(PHIIID-PHIIIS(III,ISII(III)))
- IF(PHIREL.GT.PARU(1)) PHIREL=PARU(2)-PHIREL
- IF((1.-HAZII)*(1.-HAZII*CAD)/(1.+HAZII**2-2.*HAZII*CAD)
- & .LT.RLU(0)) GOTO 470
- ENDIF
- ENDIF
-
-C...Continue loop over partons that may branch, until none left.
- IF(IGM.GE.0) K(IM,1)=14
- N=N+NEP
- NEP=2
- IF(N.GT.MSTU(4)-MSTU(32)-5) THEN
- CALL LUERRM(11,'(LUSHOW:) no more memory left in LUJETS')
- IF(MSTU(21).GE.1) N=NS
- IF(MSTU(21).GE.1) RETURN
- ENDIF
- GOTO 270
-
-C...Set information on imagined shower initiator.
- 510 IF(NPA.GE.2) THEN
- K(NS+1,1)=11
- K(NS+1,2)=94
- K(NS+1,3)=IP1
- IF(IP2.GT.0.AND.IP2.LT.IP1) K(NS+1,3)=IP2
- K(NS+1,4)=NS+2
- K(NS+1,5)=NS+1+NPA
- IIM=1
- ELSE
- IIM=0
- ENDIF
-
-C...Reconstruct string drawing information.
- DO 520 I=NS+1+IIM,N
- IF(K(I,1).LE.10.AND.K(I,2).EQ.22) THEN
- K(I,1)=1
- ELSEIF(K(I,1).LE.10.AND.IABS(K(I,2)).GE.11.AND.
- &IABS(K(I,2)).LE.18) THEN
- K(I,1)=1
- ELSEIF(K(I,1).LE.10) THEN
- K(I,4)=MSTU(5)*(K(I,4)/MSTU(5))
- K(I,5)=MSTU(5)*(K(I,5)/MSTU(5))
- ELSEIF(K(MOD(K(I,4),MSTU(5))+1,2).NE.22) THEN
- ID1=MOD(K(I,4),MSTU(5))
- IF(K(I,2).GE.1.AND.K(I,2).LE.8) ID1=MOD(K(I,4),MSTU(5))+1
- ID2=2*MOD(K(I,4),MSTU(5))+1-ID1
- K(I,4)=MSTU(5)*(K(I,4)/MSTU(5))+ID1
- K(I,5)=MSTU(5)*(K(I,5)/MSTU(5))+ID2
- K(ID1,4)=K(ID1,4)+MSTU(5)*I
- K(ID1,5)=K(ID1,5)+MSTU(5)*ID2
- K(ID2,4)=K(ID2,4)+MSTU(5)*ID1
- K(ID2,5)=K(ID2,5)+MSTU(5)*I
- ELSE
- ID1=MOD(K(I,4),MSTU(5))
- ID2=ID1+1
- K(I,4)=MSTU(5)*(K(I,4)/MSTU(5))+ID1
- K(I,5)=MSTU(5)*(K(I,5)/MSTU(5))+ID1
- IF(IABS(K(I,2)).LE.10.OR.K(ID1,1).GE.11) THEN
- K(ID1,4)=K(ID1,4)+MSTU(5)*I
- K(ID1,5)=K(ID1,5)+MSTU(5)*I
- ELSE
- K(ID1,4)=0
- K(ID1,5)=0
- ENDIF
- K(ID2,4)=0
- K(ID2,5)=0
- ENDIF
- 520 CONTINUE
-
-C...Transformation from CM frame.
- IF(NPA.GE.2) THEN
- BEX=PS(1)/PS(4)
- BEY=PS(2)/PS(4)
- BEZ=PS(3)/PS(4)
- GA=PS(4)/PS(5)
- GABEP=GA*(GA*(BEX*P(IPA(1),1)+BEY*P(IPA(1),2)+BEZ*P(IPA(1),3))
- & /(1.+GA)-P(IPA(1),4))
- ELSE
- BEX=0.
- BEY=0.
- BEZ=0.
- GABEP=0.
- ENDIF
- THE=ULANGL(P(IPA(1),3)+GABEP*BEZ,SQRT((P(IPA(1),1)
- &+GABEP*BEX)**2+(P(IPA(1),2)+GABEP*BEY)**2))
- PHI=ULANGL(P(IPA(1),1)+GABEP*BEX,P(IPA(1),2)+GABEP*BEY)
- IF(NPA.EQ.3) THEN
- CHI=ULANGL(COS(THE)*COS(PHI)*(P(IPA(2),1)+GABEP*BEX)+COS(THE)*
- & SIN(PHI)*(P(IPA(2),2)+GABEP*BEY)-SIN(THE)*(P(IPA(2),3)+GABEP*
- & BEZ),-SIN(PHI)*(P(IPA(2),1)+GABEP*BEX)+COS(PHI)*(P(IPA(2),2)+
- & GABEP*BEY))
- MSTU(33)=1
- CALL LUDBRB(NS+1,N,0.,CHI,0D0,0D0,0D0)
- ENDIF
- DBEX=DBLE(BEX)
- DBEY=DBLE(BEY)
- DBEZ=DBLE(BEZ)
- MSTU(33)=1
- CALL LUDBRB(NS+1,N,THE,PHI,DBEX,DBEY,DBEZ)
-
-C...Decay vertex of shower.
- DO 540 I=NS+1,N
- DO 530 J=1,5
- V(I,J)=V(IP1,J)
- 530 CONTINUE
- 540 CONTINUE
-
-C...Delete trivial shower, else connect initiators.
- IF(N.EQ.NS+NPA+IIM) THEN
- N=NS
- ELSE
- DO 550 IP=1,NPA
- K(IPA(IP),1)=14
- K(IPA(IP),4)=K(IPA(IP),4)+NS+IIM+IP
- K(IPA(IP),5)=K(IPA(IP),5)+NS+IIM+IP
- K(NS+IIM+IP,3)=IPA(IP)
- IF(IIM.EQ.1.AND.MSTU(16).NE.2) K(NS+IIM+IP,3)=NS+1
- IF(K(NS+IIM+IP,1).NE.1) THEN
- K(NS+IIM+IP,4)=MSTU(5)*IPA(IP)+K(NS+IIM+IP,4)
- K(NS+IIM+IP,5)=MSTU(5)*IPA(IP)+K(NS+IIM+IP,5)
- ENDIF
- 550 CONTINUE
- ENDIF
-
- RETURN
- END
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff