/
lysspa.F
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lysspa.F
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C ********************************************************************
SUBROUTINE LYSSPA(IPU1,IPU2)
IMPLICIT NONE
C...NEW X REDEFINITION
C...GENERATES SPACELIKE PARTON SHOWERS
*
* to avoid variable conflictions, a second keep element is necessary
* with the same common block name (see LEPTO2)
*
COMMON /LEPTOU/ CUT(14),LST(40),PARL(30),
& XLP,YLP,W2LP,Q2LP,ULP
REAL CUT,PARL,XLP,YLP,W2LP,Q2LP,ULP
INTEGER LST
SAVE /LEPTOU/
INTEGER NLUPDM,NPLBUF
PARAMETER (NLUPDM=4000,NPLBUF=5)
COMMON/LUJETS/N,K(NLUPDM,5),P(NLUPDM,NPLBUF),V(NLUPDM,5)
INTEGER N,K
REAL P,V
SAVE /LUJETS/
COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200)
INTEGER MSTU,MSTJ
REAL PARU,PARJ
SAVE /LUDAT1/
COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4)
INTEGER KCHG
REAL PMAS,PARF,VCKM
SAVE /LUDAT2/
COMMON /PYPARA/ IPY(80),PYPAR(80),PYVAR(80)
REAL PYPAR,PYVAR
INTEGER IPY
SAVE /PYPARA/
*
* to avoid variable conflictions, a second keep element is necessary
* with the same common block name (see LYPRO2)
*
COMMON /LYPROC/ ISUB,KFL(3,2),X(2),SH,TH,UH,Q2,XSEC(0:40)
REAL X,SH,TH,UH,Q2,XSEC
INTEGER ISUB,KFL
SAVE /LYPROC/
COMMON /LYINT1/ XQ(2,-6:6),DSIG(-6:6,-6:6,5),FSIG(10,10,3)
REAL XQ,DSIG,FSIG
SAVE /LYINT1/
INTEGER IPU1,IPU2,IFLS,IS,NQ,ILEP,IFLA,NS,IFL,JT,IHFC,IHFX,
+I,J,JR,IFLB,IHFT,IPO,I1,I2,ITEMP,IT,IKIN,ID1,KN1,KD1,ID2,
+IR,JB,NTRY,N145, NJR
REAL XS,ZS,Q2S,TEVS,ROBO,XFS,XFA,XFB,WTAP,WTSF,Z,XE0,XA,
+TMAX,QMAX,Q2E,B0,XBMIN,XB,Q2B,TEVB,QMASS,XE,WTAPQ,WTSUM,TEVXP,
+Q2REF,WTRAN,WTZ,XBNEW,RSOFT,ZU,Q2MAX,ALPRAT,THE
REAL ULMASS,RLU,ULANGL,XT,SEARATIO
DIMENSION IFLS(4),IS(2),XS(2),ZS(2),Q2S(2),TEVS(2),ROBO(5),
&XFS(2,-6:6),XFA(-6:6),XFB(-6:6),WTAP(-6:6),WTSF(-6:6)
DOUBLE PRECISION DQ2(3),DSH,DSHZ,DSHR,DPLCM,DPC(3),DPD(4),DMS,
&DMSMA,DPT2,DPB(4),DBE1(4),DBE2(4),DBEP,DGABEP,DPQ(4),DPQS(2),
&DM2,DQ2B,DROBO(5),DBEZ,DTEMP
C-GI &DQ23,DPH(4),DM2,DQ2B,DQM2
CJR--begin
LOGICAL SEAQUARK,SPLIT
REAL XFT(-6:6)
REAL XQUARK,XGLUON,XSEA,ZSPLIT,ZSOFT,ZMAX
COMMON /SEAQTE/ XQUARK,XGLUON,XSEA,ZSPLIT,ZSOFT,ZMAX,SPLIT
INTEGER LASTFL,SEAFL
COMMON /FLAVOR/ LASTFL,SEAFL
CJR--end
DATA IFLA,NQ/0,0/,Z,XE0,XA/3*0./,DSHZ,DMSMA,DPT2,DSHR/4*0.D0/
C...COMMON CONSTANTS, SET UP INITIAL VALUES
ILEP=0
IF(IPU1.EQ.0) ILEP=1
IF(IPU2.EQ.0) ILEP=2
Q2E=Q2
C-GI IF(ISET(ISUB).EQ.2.OR.ISET(ISUB).EQ.3) Q2E=Q2E/PYPAR(26)
IF(ISUB.EQ.27) Q2E=PMAS(23,1)**2
IF(ISUB.EQ.28) Q2E=PMAS(24,1)**2
TMAX=ALOG(PYPAR(26)*PYPAR(27)*Q2E/PYPAR(21)**2)
IF(ILEP.GE.1) THEN
SH=P(25,5)**2
IF(N.GE.27) SH=P(27,5)**2
CALL LSCALE(-1,QMAX)
Q2E=QMAX**2
Q2E=MAX(PYPAR(21)**2,MIN(Q2E,(0.95/X(3-ILEP)-1.)*Q2-SH,
& Q2/2.+SH))
TMAX=ALOG(Q2E/PYPAR(21)**2)
ENDIF
CJR--begin
IF (MOD(LST(8),10).EQ.4 .OR. MOD(LST(8),10).EQ.5) THEN
Q2E=PYPAR(22)
TMAX=ALOG(Q2E/PYPAR(21)**2)
ELSEIF(PYPAR(26)*Q2E.LT.MAX(PYPAR(22),2.*PYPAR(21)**2).OR.
&TMAX.LT.0.2) THEN
RETURN
ENDIF
CJR--end
IF(ILEP.EQ.0) XE0=2.*PYPAR(23)/PYVAR(1)
B0=(33.-2.*IPY(8))/6.
NS=N
MSTU(2)=0
CJR--begin
NTRY=0
100 N=NS
NTRY=NTRY+1
IF (NTRY.GT.100) THEN
LST(21)=17
RETURN
ENDIF
CJR--end
CJR 100 N=NS
CJR--begin
SEAQUARK=.FALSE.
SPLIT=.FALSE.
CJR--end
IF(ILEP.GE.1) THEN
NQ=IPU2-2
IF(ILEP.EQ.2) NQ=IPU1+2
DPQS(1)=DBLE(P(NQ,3))
DPQS(2)=DBLE(P(NQ,4))
XBMIN=X(3-ILEP)*MAX(0.5,SH/Q2)
CALL LYSTFU(IPY(43-ILEP),XBMIN,Q2,XFB)
DO 110 IFL=-6,6
110 XQ(3-ILEP,IFL)=XFB(IFL)
ENDIF
DO 120 JT=1,2
IFLS(JT)=KFL(2,JT)
IF(KFL(2,JT).EQ.21) IFLS(JT)=0
IFLS(JT+2)=IFLS(JT)
XS(JT)=X(JT)
ZS(JT)=1.
IF(ILEP.EQ.0) Q2S(JT)=PYPAR(26)*Q2E
TEVS(JT)=TMAX
DO 120 IFL=-6,6
120 XFS(JT,IFL)=XQ(JT,IFL)
IF(ILEP.GE.1) THEN
Q2S(ILEP)=P(NQ,5)**2
DQ2(ILEP)=Q2S(ILEP)
Q2S(3-ILEP)=Q2E
ENDIF
DSH=SH
IHFC=0
IHFX=0
C...PICK UP LEG WITH HIGHEST VIRTUALITY
130 CONTINUE
IF(N.GT.MSTU(4)-10) THEN
WRITE(6,*) ' LYSSPA: no more memory in LUJETS'
LST(21)=18
RETURN
ENDIF
DO 133 I=N+1,N+8
DO 133 J=1,5
K(I,J)=0
133 P(I,J)=0.
C CALL GULIST(21,2)
N=N+2
JT=1
IF((N.GT.NS+2.AND.Q2S(2).GT.Q2S(1).AND.ILEP.EQ.0).OR.ILEP.EQ.1)
&JT=2
JR=3-JT
IFLB=IFLS(JT)
XB=XS(JT)
IF(ILEP.GE.1.AND.N.EQ.NS+2) XB=XS(JT)*MAX(SH/Q2,0.5)
DO 140 IFL=-6,6
140 XFB(IFL)=XFS(JT,IFL)
Q2B=Q2S(JT)
TEVB=TEVS(JT)
IF(IPY(14).GE.9.AND.N.GT.NS+4) THEN
Q2B=0.5*(1./ZS(JT)+1.)*Q2S(JT)+0.5*(1./ZS(JT)-1.)*(Q2S(3-JT)-
& SNGL(DSH)+SQRT((SNGL(DSH)+Q2S(1)+Q2S(2))**2+8.*Q2S(1)*Q2S(2)*
& ZS(JT)/(1.-ZS(JT))))
TEVB=ALOG(PYPAR(27)*Q2B/PYPAR(21)**2)
ENDIF
IF(ILEP.EQ.0) THEN
DSHR=2.*DSQRT(DSH)
DSHZ=DSH/DBLE(ZS(JT))
ELSEIF(ILEP.GE.1) THEN
DSHZ=DSH
IF(N.GT.NS+4) DSHZ=(DSH+DQ2(JR)-DQ2(JT))/ZS(JT)-DQ2(JR)+
& PYPAR(22)
DPD(2)=DSHZ+DQ2(JR)+DBLE(PYPAR(22))
MSTJ(93)=1
QMASS=ULMASS(IABS(IFLB))
IF(IABS(IFLB).EQ.0) QMASS=ULMASS(21)
C...CHECK IF QUARK PAIR CREATION ONLY POSSIBILITY
IF(DQ2(JR).LT.4.*QMASS**2) THEN
DM2=QMASS**2
DPC(1)=DQ2(JR)*(DBLE(PYPAR(22))+DM2)**2
DPC(2)=DPD(2)*(DPD(2)-2D0*PYPAR(22))*(PYPAR(22)+DM2)
DPC(3)=PYPAR(22)*(DPD(2)-2D0*PYPAR(22))**2
XE0=1D0-(DPC(2)-DSQRT(DPC(2)**2-4D0*DPC(1)*DPC(3)))/
& (2D0*DPC(1))
CJR--begin
ZMAX=(DPC(2)-DSQRT(DPC(2)**2-4D0*DPC(1)*DPC(3)))/(2D0*DPC(1))
XE0=XB*(1./ZMAX-1.)
CJR--end
ELSE
XE0=1D0-(DPD(2)-2D0*DBLE(PYPAR(22)))*(DPD(2)-DSQRT(DPD(2)**2-
& 4D0*DQ2(JR)*DBLE(PYPAR(22))))/(2D0*DQ2(JR)*DBLE(PYPAR(22)))
CJR--begin
ZMAX=(DPD(2)-2D0*DBLE(PYPAR(22)))*(DPD(2)-DSQRT(DPD(2)**2-
& 4D0*DQ2(JR)*DBLE(PYPAR(22))))/(2D0*DQ2(JR)*DBLE(PYPAR(22)))
XE0=XB*(1./ZMAX-1.)
CJR--end
ENDIF
CJR--begin
CJR-- radiated parton energy cut
C XE0=MAX(XE0,2.*PYPAR(23)/SQRT(W2LP))
CJR--end
ENDIF
CJR 145 XE=MAX(XE0,XB*(1./(1.-PYPAR(24))-1.))
CJR--begin
N145=0
145 CONTINUE
N145=N145+1
IF (N145.GT.100) THEN
CJR WRITE(*,*) '145'
GOTO 100
ENDIF
XE=MAX(XE0,XB*(1./(1.-PYPAR(24))-1.))
ZMAX=XB/(XB+XE)
CJR--end
IF(XB+XE.GE.0.999) THEN
Q2B=0.
GOTO 210
ENDIF
C...CALCULATE ALTARELLI-PARISI AND STRUCTURE FUNCTION WEIGHTS
DO 150 IFL=-6,6
WTAP(IFL)=0.
150 WTSF(IFL)=0.
IF(IFLB.EQ.0) THEN
WTAPQ=16.*(1.-SQRT(XB+XE))/(3.*SQRT(XB))
DO 160 IFL=-IPY(8),IPY(8)
IF(IFL.EQ.0) WTAP(IFL)=6.*ALOG((1.-XB)/XE)
160 IF(IFL.NE.0) WTAP(IFL)=WTAPQ
ELSE
WTAP(0)=0.5*XB*(1./(XB+XE)-1.)
WTAP(IFLB)=8.*ALOG((1.-XB)*(XB+XE)/XE)/3.
ENDIF
170 WTSUM=0.
IF(IHFC.EQ.0) THEN
DO 180 IFL=-IPY(8),IPY(8)
WTSF(IFL)=XFB(IFL)/MAX(1E-10,XFB(IFLB))
180 WTSUM=WTSUM+WTAP(IFL)*WTSF(IFL)
IF(IABS(IFLB).GE.4.AND.WTSUM.GT.1E3) THEN
IHFX=1
DO 185 IFL=-IPY(8),IPY(8)
185 WTSF(IFL)=WTSF(IFL)*1E3/WTSUM
WTSUM=1E3
ENDIF
ENDIF
C...CHOOSE NEW T AND FLAVOUR
CJR 190 IF(IPY(14).LE.6.OR.IPY(14).GE.9) THEN
CJR--begin
NJR=0
190 CONTINUE
SEAQUARK=.FALSE.
NJR=NJR+1
IF (NJR.GT.100) THEN
CJR WRITE(*,*) '190'
GOTO 100
ENDIF
CJR--end
IF(IPY(14).LE.6.OR.IPY(14).GE.9) THEN
TEVXP=B0/MAX(0.0001,WTSUM)
ELSE
TEVXP=B0/MAX(0.0001,5.*WTSUM)
ENDIF
TEVB=TEVB*EXP(MAX(-100.,ALOG(RLU(0))*TEVXP))
Q2REF=PYPAR(21)**2*EXP(TEVB)/PYPAR(27)
Q2B=Q2REF/PYPAR(27)
DQ2B=Q2B
IF(ILEP.GE.1) THEN
DSHZ=DSH
IF(N.GT.NS+4) DSHZ=(DSH+DQ2(JR)-DQ2(JT))/DBLE(ZS(JT))-DQ2(JR)+
& DQ2B
ENDIF
CJR--begin --
CAE--seaquarks up to LST(12), if the quark density != 0
IF( LST(35).EQ.1) THEN
IF( Q2B.LT.PYPAR(22) .AND.
& (ABS(IFLB).LE.LST(12).AND.ABS(IFLB).GE.1)) THEN
Q2REF=MIN(PYPAR(22),Q2S(JT))
Q2B=MIN(PYPAR(22),Q2S(JT))
IF(ILEP.GE.1.AND.N.EQ.NS+2) THEN
XT=X(JT)*(1.+(DSH-Q2B)/DQ2(JR))
ELSE
XT=XB
ENDIF
CALL LYSTFU(IPY(40+JT),XT,Q2REF,XFT)
IF(XFT(IFLB).EQ.0.0.AND.XFT(-IFLB).EQ.0.0) THEN
SEARATIO=1.0
ELSEIF(XFT(ABS(IFLB)).EQ.0.0) THEN
SEARATIO=1.0
ELSE
SEARATIO=XFT(-ABS(IFLB))/XFT(ABS(IFLB))
ENDIF
CJR-- (protons only)
IF (RLU(0).LT.SEARATIO) THEN
SEAQUARK=.TRUE.
XQUARK=XT
ELSE
Q2B=0.
SEAQUARK=.FALSE.
ENDIF
ENDIF
ENDIF
CJR--end
IF(Q2B.LT.PYPAR(22)) THEN
Q2B=0.
CJR--begin
SEAQUARK=.FALSE.
CJR--end
ELSE
WTRAN=RLU(0)*WTSUM
IFLA=-IPY(8)-1
200 IFLA=IFLA+1
WTRAN=WTRAN-WTAP(IFLA)*WTSF(IFLA)
IF(IFLA.LT.IPY(8).AND.WTRAN.GT.0.) GOTO 200
CJR--begin
IF (SEAQUARK) THEN
SEAFL=-IFLB
IFLA=0
CT XE=XB*(1./(1.-0.001)-1.)
ENDIF
CJR--end
C...CHOOSE Z VALUE AND CORRECTIVE WEIGHT
IF(IFLB.EQ.0.AND.IFLA.EQ.0) THEN
Z=1./(1.+((1.-XB)/XB)*(XE/(1.-XB))**RLU(0))
WTZ=(1.-Z*(1.-Z))**2
ELSEIF(IFLB.EQ.0) THEN
Z=XB/(1.-RLU(0)*(1.-SQRT(XB+XE)))**2
WTZ=0.5*(1.+(1.-Z)**2)*SQRT(Z)
ELSEIF(IFLA.EQ.0) THEN
Z=XB*(1.+RLU(0)*(1./(XB+XE)-1.))
WTZ=1.-2.*Z*(1.-Z)
ELSE
Z=1.-(1.-XB)*(XE/((XB+XE)*(1.-XB)))**RLU(0)
WTZ=0.5*(1.+Z**2)
ENDIF
CJR--begin
C IF (SEAQUARK) THEN
C XSEA=LEXSEA(0.15*XT,Q2B)
C XE=MIN(XE,XSEA)
C Z=XT/(XSEA+XT)
C ENDIF
CJR--end
C...REWEIGHT FIRST LEG BECAUSE OF MODIFIED XB OR CHECK PHASE SPACE
IF(ILEP.GE.1.AND.N.EQ.NS+2) THEN
XBNEW=X(JT)*(1.+(DSH-Q2B)/DQ2(JR))
IF(XBNEW.GT.MIN(Z,0.999)) GOTO 190
XB=XBNEW
ENDIF
C...SUM UP SOFT GLUON EMISSION AS EFFECTIVE Z SHIFT
CJR-- should this realy always be done ??
IF(IPY(15).GE.1) THEN
RSOFT=6.
IF(IFLB.NE.0) RSOFT=8./3.
Z=Z*(TEVB/TEVS(JT))**(RSOFT*XE/((XB+XE)*B0))
IF(Z.LE.XB) GOTO 190
CJR--begin
ZSOFT=(TEVB/TEVS(JT))**(RSOFT*XE/((XB+XE)*B0))
ZMAX=XB/(XB+XE)
CJR--end
ENDIF
C...CHECK IF HEAVY FLAVOUR BELOW THRESHOLD
IHFT=0
CIC...Skip for intrinsic charm/bottom simulation, charm quark should
CIC...not come from gluon but is non-perturbative part of proton.
IF(LST(15).EQ.-4.OR.LST(15).EQ.-5) GOTO 205
MSTJ(93)=1
IF(ILEP.GE.1.AND.IABS(IFLB).GE.4.AND.(XFB(IFLB).LT.1E-10.OR.
& Q2B.LT.5.*ULMASS(IABS(IFLB))**2)) THEN
IHFT=1
IFLA=0
ENDIF
205 CONTINUE
C...FOR LEPTOPRODUCTION, CHECK Z AGAINST NEW LIMIT
IF(ILEP.GE.1) THEN
DPD(2)=DSHZ+DQ2(JR)+DQ2B
MSTJ(93)=1
DM2=ULMASS(IABS(IFLA-IFLB))**2
IF(IABS(IFLA-IFLB).EQ.0) DM2=ULMASS(21)**2
DPC(1)=DQ2(JR)*(DQ2B+DM2)**2
DPC(2)=DPD(2)*(DPD(2)-2D0*DQ2B)*(DQ2B+DM2)
DPC(3)=DQ2B*(DPD(2)-2D0*DQ2B)**2
ZU=(DPC(2)-DSQRT(DPC(2)**2-4D0*DPC(1)*DPC(3)))/(2D0*DPC(1))
IF(Z.GE.ZU) GOTO 190
ENDIF
C...OPTION WITH EVOLUTION IN KT2=(1-Z)Q2:
IF(IPY(14).GE.5.AND.IPY(14).LE.6.AND.N.LE.NS+4) THEN
C...CHECK THAT (Q2)LAST BRANCHING < (Q2)HARD
IF(Q2B/(1.-Z).GT.PYPAR(26)*Q2) GOTO 190
ELSEIF(IPY(14).GE.3.AND.IPY(14).LE.6.AND.N.GE.NS+6) THEN
C...CHECK THAT Z,Q2 COMBINATION IS KINEMATICALLY ALLOWED
Q2MAX=0.5*(1./ZS(JT)+1.)*DQ2(JT)+0.5*(1./ZS(JT)-1.)*
& (DQ2(3-JT)-DSH+SQRT((DSH+DQ2(1)+DQ2(2))**2+8.*DQ2(1)*DQ2(2)*
& ZS(JT)/(1.-ZS(JT))))
IF(Q2B/(1.-Z).GE.Q2MAX) GOTO 190
ELSEIF(IPY(14).EQ.7.OR.IPY(14).EQ.8) THEN
C...OPTION WITH ALPHAS((1-Z)Q2): DEMAND KT2 > CUTOFF, REWEIGHT
IF((1.-Z)*Q2B.LT.PYPAR(22)) GOTO 190
ALPRAT=TEVB/(TEVB+ALOG(1.-Z))
IF(ALPRAT.LT.5.*RLU(0)) GOTO 190
IF(ALPRAT.GT.5.) WTZ=WTZ*ALPRAT/5.
ENDIF
C...WEIGHTING WITH NEW STRUCTURE FUNCTIONS
CALL LYSTFU(IPY(40+JT),XB,Q2REF,XFB)
XA=XB/Z
CALL LYSTFU(IPY(40+JT),XA,Q2REF,XFA)
IF(IHFT.EQ.1.OR.IHFX.EQ.1) THEN
IF(XFA(IFLA).LT.1E-10) IHFC=1
GOTO 210
ELSEIF(XFB(IFLB).LT.1E-20) THEN
GOTO 100
ENDIF
IF(WTZ*XFA(IFLA)/XFB(IFLB).LT.RLU(0)*WTSF(IFLA)) THEN
IF(ILEP.GE.1.AND.N.EQ.NS+2) GOTO 145
GOTO 170
ENDIF
CJR--begin
IF (SEAQUARK) THEN
SPLIT=.TRUE.
XGLUON=XA
XSEA=XA-XB
ZSPLIT=Z
SEAQUARK=.FALSE.
ENDIF
CJR--end
ENDIF
210 CONTINUE
IF(N.EQ.NS+4-2*MIN(1,ILEP)) THEN
C...DEFINE TWO HARD SCATTERERS IN THEIR CM-FRAME
DQ2(JT)=Q2B
IF(IPY(14).GE.3.AND.IPY(14).LE.6) DQ2(JT)=Q2B/(1.-Z)
IF(ILEP.EQ.0) THEN
DPLCM=DSQRT((DSH+DQ2(1)+DQ2(2))**2-4.*DQ2(1)*DQ2(2))/DSHR
DO 220 JR=1,2
I=NS+2*JR-1
IPO=19+2*JR
K(I,1)=14
K(I,2)=IFLS(JR+2)
IF(IFLS(JR+2).EQ.0) K(I,2)=21
K(I,3)=0
K(I,4)=IPO
K(I,5)=IPO
P(I,1)=0.
P(I,2)=0.
P(I,3)=DPLCM*(-1)**(JR+1)
P(I,4)=(DSH+DQ2(3-JR)-DQ2(JR))/DSHR
P(I,5)=-SQRT(SNGL(DQ2(JR)))
K(I+1,1)=-1
K(I+1,2)=K(IPO+1,2)
K(I+1,3)=I
K(I+1,4)=0
K(I+1,5)=0
P(I+1,1)=0.
P(I+1,2)=0.
P(I+1,3)=IPO
P(I+1,4)=IPO
P(I+1,5)=0.
P(IPO+1,1)=I
P(IPO+1,2)=I
K(IPO,4)=MOD(K(IPO,4),MSTU(5))+I*MSTU(5)
K(IPO,5)=MOD(K(IPO,5),MSTU(5))+I*MSTU(5)
220 CONTINUE
ELSE
C..LEPTOPRODUCTION EVENTS: BOSON AND HADRON REST FRAME
I1=NS+2*ILEP-1
I2=NS-2*ILEP+5
DO 225 ITEMP=NS+1,NS+4
DO 225 J=1,5
K(ITEMP,J)=0
225 P(ITEMP,J)=0.
DO 230 J=1,5
230 P(I1,J)=P(NQ,J)
K(NS+1,1)=11
K(NS+3,1)=14
IF(ILEP.EQ.2) THEN
K(NS+1,1)=14
K(NS+3,1)=11
ENDIF
K(NS+2,1)=-1
K(NS+4,1)=-1
K(NS+1,3)=0
K(NS+2,3)=NS+1
K(NS+3,3)=0
K(NS+4,3)=NS+3
K(I1,2)=KFL(2,ILEP)
K(I2,2)=KFL(2,3-ILEP)
DPD(1)=DSH+DQ2(1)+DQ2(2)
DPD(3)=(3-2*ILEP)*DSQRT(DPD(1)**2-4D0*DQ2(1)*DQ2(2))
P(I2,3)=(DPQS(2)*DPD(3)-DPQS(1)*DPD(1))/
& (2D0*DQ2(JR))
P(I2,4)=(DPQS(1)*DPD(3)-DPQS(2)*DPD(1))/
& (2D0*DQ2(JR))
P(I2,5)=-SQRT(SNGL(DQ2(3-ILEP)))
P(I2+1,3)=MAX(IPU1,IPU2)
P(I2+1,4)=MAX(IPU1,IPU2)
K(I2,4)=K(I2,4)-MOD(K(I2,4),MSTU(5))+MAX(IPU1,IPU2)
K(I2,5)=K(I2,5)-MOD(K(I2,5),MSTU(5))+MAX(IPU1,IPU2)
P(26-2*ILEP,1)=I2
P(26-2*ILEP,2)=I2
K(25-2*ILEP,4)=MOD(K(25-2*ILEP,4),MSTU(5))+I2*MSTU(5)
K(25-2*ILEP,5)=MOD(K(25-2*ILEP,5),MSTU(5))+I2*MSTU(5)
N=N+2
ENDIF
ELSEIF(N.GT.NS+4) THEN
C...FIND MAXIMUM ALLOWED MASS OF TIMELIKE PARTON
DQ2(3)=Q2B
IF(IPY(14).GE.3.AND.IPY(14).LE.6) DQ2(3)=Q2B/(1.-Z)
IF(IS(1).GE.1.AND.IS(1).LE.MSTU(4)) THEN
DPC(1)=P(IS(1),4)
DPC(3)=0.5*(ABS(P(IS(1),3))+ABS(P(IS(2),3)))
ELSE
C...IS(1) not initialized
DPC(1)=0.
DPC(3)=0.5*( 0. +ABS(P(IS(2),3)))
ENDIF
DPC(2)=P(IS(2),4)
DPD(1)=DSH+DQ2(JR)+DQ2(JT)
DPD(2)=DSHZ+DQ2(JR)+DQ2(3)
DPD(3)=DSQRT(DPD(1)**2-4.*DQ2(JR)*DQ2(JT))
DPD(4)=DSQRT(DPD(2)**2-4.*DQ2(JR)*DQ2(3))
IKIN=0
IF((Q2S(JR).GE.0.5*PYPAR(22).AND.DPD(1)-DPD(3).GE.1D-10*DPD(1))
& .OR.ILEP.GE.1) IKIN=1
IF(IKIN.EQ.0) DMSMA=(DQ2(JT)/DBLE(ZS(JT))-DQ2(3))*(DSH/
& (DSH+DQ2(JT))-DSH/(DSHZ+DQ2(3)))
IF(IKIN.EQ.1) DMSMA=(DPD(1)*DPD(2)-DPD(3)*DPD(4))/(2.*
& DQ2(JR))-DQ2(JT)-DQ2(3)
C...GENERATE TIMELIKE PARTON SHOWER (IF REQUIRED)
IT=N-1
K(IT,1)=3
K(IT,2)=IFLB-IFLS(JT+2)
IF(IFLB-IFLS(JT+2).EQ.0) K(IT,2)=21
MSTJ(93)=1
P(IT,5)=ULMASS(K(IT,2))
IF(SNGL(DMSMA).LE.P(IT,5)**2) GOTO 100
P(IT,2)=0.
DO 240 J=1,5
K(IT+1,J)=0
240 P(IT+1,J)=0.
K(IT+1,1)=-1
K(IT+1,2)=K(IS(JT)+1,2)
K(IT+1,3)=IT
IF(MOD(IPY(14),2).EQ.0) THEN
P(IT,1)=0.
IF(ILEP.EQ.0) P(IT,4)=(DSHZ-DSH-P(IT,5)**2)/DSHR
IF(ILEP.GE.1) P(IT,4)=0.5*(P(IS(JT),3)*DPD(2)+
& DPQS(1)*(DQ2(JT)+DQ2(3)+P(IT,5)**2))/(P(IS(JT),3)*DPQS(2)-
& P(IS(JT),4)*DPQS(1))-DPC(JT)
P(IT,3)=SQRT(MAX(0.,P(IT,4)**2-P(IT,5)**2))
CALL LUSHOW(IT,0,SQRT(MIN(SNGL(DMSMA),PYPAR(25)*Q2)))
IF(N.GE.IT+2) P(IT,5)=P(IT+2,5)
IF(N.GT.MSTU(4)-10) THEN
WRITE(6,*) ' LYSSPA: no more memory in LUJETS'
LST(21)=19
RETURN
ENDIF
DO 243 I=N+1,N+8
DO 243 J=1,5
K(I,J)=0
243 P(I,J)=0.
ENDIF
C...RECONSTRUCT KINEMATICS OF BRANCHING: TIMELIKE PARTON SHOWER
DMS=P(IT,5)**2
IF(IKIN.EQ.0.AND.ILEP.EQ.0) DPT2=(DMSMA-DMS)*(DSHZ+DQ2(3))/
& (DSH+DQ2(JT))
IF(IKIN.EQ.1.AND.ILEP.EQ.0) DPT2=(DMSMA-DMS)*(0.5*DPD(1)*
& DPD(2)+0.5*DPD(3)*DPD(4)-DQ2(JR)*(DQ2(JT)+DQ2(3)+DMS))/
& (4.*DSH*DPC(3)**2)
IF(IKIN.EQ.1.AND.ILEP.GE.1) DPT2=(DMSMA-DMS)*(0.5*DPD(1)*
& DPD(2)+0.5*DPD(3)*DPD(4)-DQ2(JR)*(DQ2(JT)+DQ2(3)+DMS))/
& DPD(3)**2
IF(DPT2.LT.0.) GOTO 100
K(IT,3)=N+1
P(IT,1)=SQRT(SNGL(DPT2))
IF(ILEP.EQ.0) THEN
DPB(1)=(0.5*DPD(2)-DPC(JR)*(DSHZ+DQ2(JR)-DQ2(JT)-DMS)/
& DSHR)/DPC(3)-DPC(3)
P(IT,3)=DPB(1)*(-1)**(JT+1)
P(IT,4)=(DSHZ-DSH-DMS)/DSHR
ELSE
DPC(3)=DQ2(JT)+DQ2(3)+DMS
DPB(2)=DPQS(2)*DBLE(P(IS(JT),3))-DPQS(1)*DPC(JT)
DPB(1)=0.5D0*(DPC(JT)*DPD(2)+DPQS(2)*DPC(3))/DPB(2)-
& DBLE(P(IS(JT),3))
P(IT,3)=DPB(1)
P(IT,4)=0.5D0*(DBLE(P(IS(JT),3))*DPD(2)+
& DPQS(1)*DPC(3))/DPB(2)-DPC(JT)
ENDIF
IF(N.GE.IT+2) THEN
MSTU(1)=IT+2
DPB(1)=DSQRT(DPB(1)**2+DPT2)
DPB(2)=DSQRT(DPB(1)**2+DMS)
DPB(3)=P(IT+2,3)
DPB(4)=DSQRT(DPB(3)**2+DMS)
DBEZ=(DPB(4)*DPB(1)-DPB(3)*DPB(2))/(DPB(4)*DPB(2)-DPB(3)*
& DPB(1))
CALL LUDBRB(MSTU(1),MSTU(2),0.,0.,0.D0,0.D0,DBEZ)
THE=ULANGL(P(IT,3),P(IT,1))
CALL LUDBRB(MSTU(1),MSTU(2),THE,0.,0.D0,0.D0,0.D0)
ENDIF
C...RECONSTRUCT KINEMATICS OF BRANCHING: SPACELIKE PARTON
K(N+1,1)=14
K(N+1,2)=IFLB
IF(IFLB.EQ.0) K(N+1,2)=21
K(N+1,3)=0
CJR--begin
CJR-- give all radiated partons 5 as mother particle
K(N+1,3)=5
CJR--end
P(N+1,1)=P(IT,1)
P(N+1,2)=0.
P(N+1,3)=P(IT,3)+P(IS(JT),3)
P(N+1,4)=P(IT,4)+P(IS(JT),4)
P(N+1,5)=-SQRT(SNGL(DQ2(3)))
DO 250 J=1,5
K(N+2,J)=0
250 P(N+2,J)=0.
K(N+2,1)=-1
K(N+2,2)=K(IS(JT)+1,2)
K(N+2,3)=N+1
C...DEFINE COLOUR FLOW OF BRANCHING
K(IS(JT),1)=14
K(IS(JT),3)=N+1
ID1=IT
KN1=ISIGN(500+IABS(K(N+1,2)),2*K(N+1,2)+1)
KD1=ISIGN(500+IABS(K(ID1,2)),2*K(ID1,2)+1)
IF(K(N+1,2).EQ.21) KN1=500
IF(K(ID1,2).EQ.21) KD1=500
IF((KN1.GE.501.AND.KD1.GE.501).OR.(KN1.LT.0.AND.
& KD1.EQ.500).OR.(KN1.EQ.500.AND.KD1.EQ.500.AND.
& RLU(0).GT.0.5).OR.(KN1.EQ.500.AND.KD1.LT.0))
& ID1=IS(JT)
ID2=IT+IS(JT)-ID1
P(N+2,3)=ID1
P(N+2,4)=ID2
P(ID1+1,1)=N+1
P(ID1+1,2)=ID2
P(ID2+1,1)=ID1
P(ID2+1,2)=N+1
K(N+1,4)=K(N+1,4)-MOD(K(N+1,4),MSTU(5))+ID1
K(N+1,5)=K(N+1,5)-MOD(K(N+1,5),MSTU(5))+ID2
K(ID1,4)=MOD(K(ID1,4),MSTU(5))+(N+1)*MSTU(5)
K(ID1,5)=MOD(K(ID1,5),MSTU(5))+ID2*MSTU(5)
K(ID2,4)=MOD(K(ID2,4),MSTU(5))+ID1*MSTU(5)
K(ID2,5)=MOD(K(ID2,5),MSTU(5))+(N+1)*MSTU(5)
N=N+2
C CALL GULIST(22,2)
C...BOOST TO NEW CM-FRAME
MSTU(1)=NS+1
IF(ILEP.EQ.0) THEN
CALL LUDBRB(MSTU(1),MSTU(2),0.,0.,
& -DBLE(P(N-1,1)+P(IS(JR),1))/DBLE(P(N-1,4)+P(IS(JR),4)),
& 0.D0,-DBLE(P(N-1,3)+P(IS(JR),3))/DBLE(P(N-1,4)+P(IS(JR),4)))
IR=N-1+(JT-1)*(IS(1)-N+1)
CALL LUDBRB(MSTU(1),MSTU(2),
& -ULANGL(P(IR,3),P(IR,1)),PARU(2)*RLU(0),0.D0,0.D0,0.D0)
ELSE
C...REORIENTATE EVENT WITHOUT CHANGING THE BOSON FOUR MOMENTUM
DO 260 J=1,4
260 DPQ(J)=P(NQ,J)
DBE1(4)=DPQ(4)+DBLE(P(N-1,4))
DO 270 J=1,3,2
270 DBE1(J)=-(DPQ(J)+DBLE(P(N-1,J)))/DBE1(4)
DTEMP=1.D0-DBE1(1)**2-DBE1(3)**2
IF(DTEMP.LE.0.D0) THEN
LST(21)=20
IF(LST(3).GE.1) WRITE(6,*) ' Warning from LYSSPA: sqrt of',
& DTEMP,' New event generated.'
RETURN
ENDIF
DBE1(4)=1.D0/DSQRT(DTEMP)
DBEP=DBE1(1)*DPQ(1)+DBE1(3)*DPQ(3)
DGABEP=DBE1(4)*(DBE1(4)*DBEP/(1D0+DBE1(4))+DPQ(4))
DO 280 J=1,3,2
280 DPQ(J)=DPQ(J)+DGABEP*DBE1(J)
DPQ(4)=DBE1(4)*(DPQ(4)+DBEP)
DPC(1)=DSQRT(DPQ(1)**2+DPQ(3)**2)
DBE2(4)=-(DPQ(4)*DPC(1)-DPQS(2)*DSQRT(DPQS(2)**2+DPC(1)**2-
& DPQ(4)**2))/(DPC(1)**2+DPQS(2)**2)
THE=ULANGL(SNGL(DPQ(3)),SNGL(DPQ(1)))
DBE2(1)=DBE2(4)*DSIN(DBLE(THE))
DBE2(3)=DBE2(4)*DCOS(DBLE(THE))
DBE2(4)=1D0/(1D0-DBE2(1)**2-DBE2(3)*2)
C...CONSTRUCT THE COMBINED BOOST
DPB(1)=DBE1(4)**2*DBE2(4)/(1D0+DBE1(4))
DPB(2)=DBE1(1)*DBE2(1)+DBE1(3)*DBE2(3)
DPB(3)=DBE1(4)*DBE2(4)*(1D0+DPB(2))
DO 290 JB=1,3,2
290 DROBO(JB+2)=(DBE1(4)*DBE2(4)*DBE1(JB)+DBE2(4)*DBE2(JB)+
& DPB(1)*DBE1(JB)*DPB(2))/DPB(3)
CALL LUDBRB(MSTU(1),MSTU(2),0.,0.,DROBO(3),0.D0,DROBO(5))
IF(ILEP.EQ.1) THE=ULANGL(P(NS+1,3),P(NS+1,1))
IF(ILEP.EQ.2) THE=PARU(1)+ULANGL(P(NS+3,3),P(NS+3,1))
CALL LUDBRB(MSTU(1),MSTU(2),-THE,PARU(2)*RLU(0),0D0,0D0,0D0)
ENDIF
MSTU(1)=0
ENDIF
C...SAVE QUANTITIES, LOOP BACK
IS(JT)=N-1
IF(ILEP.EQ.2.AND.N.EQ.NS+4) IS(JT)=N-3
Q2S(JT)=Q2B
DQ2(JT)=Q2B
IF(IPY(14).GE.3.AND.IPY(14).LE.6) DQ2(JT)=Q2B/(1.-Z)
DSH=DSHZ
IF(Q2B.GE.0.5*PYPAR(22)) THEN
IFLS(JT+2)=IFLS(JT)
IFLS(JT)=IFLA
XS(JT)=XA
ZS(JT)=Z
DO 300 IFL=-6,6
300 XFS(JT,IFL)=XFA(IFL)
TEVS(JT)=TEVB
ELSE
IF(JT.EQ.1) IPU1=N-1
IF(JT.EQ.2) IPU2=N-1
ENDIF
IF(MAX(IABS(1-ILEP)*Q2S(1),MIN(1,2-ILEP)*Q2S(2)).GE.0.5*PYPAR(22)
&.OR.N.LE.NS+2) GOTO 130
IF(ILEP.EQ.0) THEN
C...BOOST HARD SCATTERING PARTONS TO FRAME OF SHOWER INITIATORS
DO 310 J=1,3
310 DROBO(J+2)=(P(NS+1,J)+P(NS+3,J))/(P(NS+1,4)+P(NS+3,4))
DO 320 J=1,5
320 P(N+2,J)=P(NS+1,J)
MSTU(1)=N+2
MSTU(2)=N+2
CALL LUDBRB(N+2,N+2,0.,0.,-DROBO(3),-DROBO(4),-DROBO(5))
ROBO(2)=ULANGL(P(N+2,1),P(N+2,2))
ROBO(1)=ULANGL(P(N+2,3),SQRT(P(N+2,1)**2+P(N+2,2)**2))
MSTU(1)=4
MSTU(2)=NS
CALL LUDBRB(4,NS,ROBO(1),ROBO(2),DROBO(3),DROBO(4),DROBO(5))
MSTU(1)=0
MSTU(2)=0
ENDIF
C...STORE USER INFORMATION
K(21,1)=14
IF(ILEP.NE.0) K(21,1)=11
K(23,1)=14
K(21,3)=NS+1
K(23,3)=NS+3
DO 330 JT=1,2
KFL(1,JT)=IFLS(JT)
IF(IFLS(JT).EQ.0) KFL(1,JT)=21
330 PYVAR(30+JT)=XS(JT)
DO 340 I=NS+1,N
DO 340 J=1,5
340 V(I,J)=0.
CJR--begin
LASTFL=IFLA
CJR--end
RETURN
END