--- /dev/null
+
+C*********************************************************************
+
+ SUBROUTINE LUONIA(KFL,ECM)
+
+C...Purpose: to generate Upsilon and toponium decays into three
+C...gluons or two gluons and a photon.
+ 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/
+
+C...Printout. Check input parameters.
+ IF(MSTU(12).GE.1) CALL LULIST(0)
+ IF(KFL.LT.0.OR.KFL.GT.8) THEN
+ CALL LUERRM(16,'(LUONIA:) called with unknown flavour code')
+ IF(MSTU(21).GE.1) RETURN
+ ENDIF
+ IF(ECM.LT.PARJ(127)+2.02*PARF(101)) THEN
+ CALL LUERRM(16,'(LUONIA:) called with too small CM energy')
+ IF(MSTU(21).GE.1) RETURN
+ ENDIF
+
+C...Initial e+e- and onium state (optional).
+ NC=0
+ IF(MSTJ(115).GE.2) THEN
+ NC=NC+2
+ CALL LU1ENT(NC-1,11,0.5*ECM,0.,0.)
+ K(NC-1,1)=21
+ CALL LU1ENT(NC,-11,0.5*ECM,PARU(1),0.)
+ K(NC,1)=21
+ ENDIF
+ KFLC=IABS(KFL)
+ IF(MSTJ(115).GE.3.AND.KFLC.GE.5) THEN
+ NC=NC+1
+ KF=110*KFLC+3
+ MSTU10=MSTU(10)
+ MSTU(10)=1
+ P(NC,5)=ECM
+ CALL LU1ENT(NC,KF,ECM,0.,0.)
+ K(NC,1)=21
+ K(NC,3)=1
+ MSTU(10)=MSTU10
+ ENDIF
+
+C...Choose x1 and x2 according to matrix element.
+ NTRY=0
+ 100 X1=RLU(0)
+ X2=RLU(0)
+ X3=2.-X1-X2
+ IF(X3.GE.1..OR.((1.-X1)/(X2*X3))**2+((1.-X2)/(X1*X3))**2+
+ &((1.-X3)/(X1*X2))**2.LE.2.*RLU(0)) GOTO 100
+ NTRY=NTRY+1
+ NJET=3
+ IF(MSTJ(101).LE.4) CALL LU3ENT(NC+1,21,21,21,ECM,X1,X3)
+ IF(MSTJ(101).GE.5) CALL LU3ENT(-(NC+1),21,21,21,ECM,X1,X3)
+
+C...Photon-gluon-gluon events. Small system modifications. Jet origin.
+ MSTU(111)=MSTJ(108)
+ IF(MSTJ(108).EQ.2.AND.(MSTJ(101).EQ.0.OR.MSTJ(101).EQ.1))
+ &MSTU(111)=1
+ PARU(112)=PARJ(121)
+ IF(MSTU(111).EQ.2) PARU(112)=PARJ(122)
+ QF=0.
+ IF(KFLC.NE.0) QF=KCHG(KFLC,1)/3.
+ RGAM=7.2*QF**2*PARU(101)/ULALPS(ECM**2)
+ MK=0
+ ECMC=ECM
+ IF(RLU(0).GT.RGAM/(1.+RGAM)) THEN
+ IF(1.-MAX(X1,X2,X3).LE.MAX((PARJ(126)/ECM)**2,PARJ(125)))
+ & NJET=2
+ IF(NJET.EQ.2.AND.MSTJ(101).LE.4) CALL LU2ENT(NC+1,21,21,ECM)
+ IF(NJET.EQ.2.AND.MSTJ(101).GE.5) CALL LU2ENT(-(NC+1),21,21,ECM)
+ ELSE
+ MK=1
+ ECMC=SQRT(1.-X1)*ECM
+ IF(ECMC.LT.2.*PARJ(127)) GOTO 100
+ K(NC+1,1)=1
+ K(NC+1,2)=22
+ K(NC+1,4)=0
+ K(NC+1,5)=0
+ IF(MSTJ(101).GE.5) K(NC+2,4)=MSTU(5)*(NC+3)
+ IF(MSTJ(101).GE.5) K(NC+2,5)=MSTU(5)*(NC+3)
+ IF(MSTJ(101).GE.5) K(NC+3,4)=MSTU(5)*(NC+2)
+ IF(MSTJ(101).GE.5) K(NC+3,5)=MSTU(5)*(NC+2)
+ NJET=2
+ IF(ECMC.LT.4.*PARJ(127)) THEN
+ MSTU10=MSTU(10)
+ MSTU(10)=1
+ P(NC+2,5)=ECMC
+ CALL LU1ENT(NC+2,83,0.5*(X2+X3)*ECM,PARU(1),0.)
+ MSTU(10)=MSTU10
+ NJET=0
+ ENDIF
+ ENDIF
+ DO 110 IP=NC+1,N
+ K(IP,3)=K(IP,3)+(MSTJ(115)/2)+(KFLC/5)*(MSTJ(115)/3)*(NC-1)
+ 110 CONTINUE
+
+C...Differential cross-sections. Upper limit for cross-section.
+ IF(MSTJ(106).EQ.1) THEN
+ SQ2=SQRT(2.)
+ HF1=1.-PARJ(131)*PARJ(132)
+ HF3=PARJ(133)**2
+ CT13=(X1*X3-2.*X1-2.*X3+2.)/(X1*X3)
+ ST13=SQRT(1.-CT13**2)
+ SIGL=0.5*X3**2*((1.-X2)**2+(1.-X3)**2)*ST13**2
+ SIGU=(X1*(1.-X1))**2+(X2*(1.-X2))**2+(X3*(1.-X3))**2-SIGL
+ SIGT=0.5*SIGL
+ SIGI=(SIGL*CT13/ST13+0.5*X1*X3*(1.-X2)**2*ST13)/SQ2
+ SIGMAX=(2.*HF1+HF3)*ABS(SIGU)+2.*(HF1+HF3)*ABS(SIGL)+2.*(HF1+
+ & 2.*HF3)*ABS(SIGT)+2.*SQ2*(HF1+2.*HF3)*ABS(SIGI)
+
+C...Angular orientation of event.
+ 120 CHI=PARU(2)*RLU(0)
+ CTHE=2.*RLU(0)-1.
+ PHI=PARU(2)*RLU(0)
+ CCHI=COS(CHI)
+ SCHI=SIN(CHI)
+ C2CHI=COS(2.*CHI)
+ S2CHI=SIN(2.*CHI)
+ THE=ACOS(CTHE)
+ STHE=SIN(THE)
+ C2PHI=COS(2.*(PHI-PARJ(134)))
+ S2PHI=SIN(2.*(PHI-PARJ(134)))
+ SIG=((1.+CTHE**2)*HF1+STHE**2*C2PHI*HF3)*SIGU+2.*(STHE**2*HF1-
+ & STHE**2*C2PHI*HF3)*SIGL+2.*(STHE**2*C2CHI*HF1+((1.+CTHE**2)*
+ & C2CHI*C2PHI-2.*CTHE*S2CHI*S2PHI)*HF3)*SIGT-2.*SQ2*(2.*STHE*CTHE*
+ & CCHI*HF1-2.*STHE*(CTHE*CCHI*C2PHI-SCHI*S2PHI)*HF3)*SIGI
+ IF(SIG.LT.SIGMAX*RLU(0)) GOTO 120
+ CALL LUDBRB(NC+1,N,0.,CHI,0D0,0D0,0D0)
+ CALL LUDBRB(NC+1,N,THE,PHI,0D0,0D0,0D0)
+ ENDIF
+
+C...Generate parton shower. Rearrange along strings and check.
+ IF(MSTJ(101).GE.5.AND.NJET.GE.2) THEN
+ CALL LUSHOW(NC+MK+1,-NJET,ECMC)
+ MSTJ14=MSTJ(14)
+ IF(MSTJ(105).EQ.-1) MSTJ(14)=-1
+ IF(MSTJ(105).GE.0) MSTU(28)=0
+ CALL LUPREP(0)
+ MSTJ(14)=MSTJ14
+ IF(MSTJ(105).GE.0.AND.MSTU(28).NE.0) GOTO 100
+ ENDIF
+
+C...Generate fragmentation. Information for LUTABU:
+ IF(MSTJ(105).EQ.1) CALL LUEXEC
+ MSTU(161)=110*KFLC+3
+ MSTU(162)=0
+
+ RETURN
+ END