ISAJET/code/elctrn.F

   1 #include "isajet/pilot.h"
   2       SUBROUTINE ELCTRN
   3 C          GENERATE E+ E- ----> QK QB EVENT USING SIGEE CROSS SECTION.
   4 #include "isajet/itapes.inc"
   5 #include "isajet/jetsig.inc"
   6 #include "isajet/eepar.inc"
   7 #include "isajet/primar.inc"
   8 #include "isajet/pjets.inc"
   9 #include "isajet/pinits.inc"
  10 #include "isajet/jetpar.inc"
  11 #include "isajet/jetlim.inc"
  12 #include "isajet/const.inc"
  13 #include "isajet/totals.inc"
  14 #include "isajet/partcl.inc"
  15 #include "isajet/xmssm.inc"
  16 #include "isajet/sstype.inc"
  17       REAL AMQ(2),SSXLAM,RSH,XD,GAM,V,DUMMY
  18       INTEGER MSUPL,MSDNL,MSSTL,MSCHL,MSBT1,MSTP1,
  19      $MSUPR,MSDNR,MSSTR,MSCHR,MSBT2,MSTP2,MSW1,MSW2,
  20      $MSNEL,MSEL,MSNML,MSMUL,MSNTL,MSTAU1,MSER,MSMUR,MSTAU2,IDSS(85)
  21       PARAMETER (MSUPL=-ISUPL)
  22       PARAMETER (MSDNL=-ISDNL)
  23       PARAMETER (MSSTL=-ISSTL)
  24       PARAMETER (MSCHL=-ISCHL)
  25       PARAMETER (MSBT1=-ISBT1)
  26       PARAMETER (MSTP1=-ISTP1)
  27       PARAMETER (MSUPR=-ISUPR)
  28       PARAMETER (MSDNR=-ISDNR)
  29       PARAMETER (MSSTR=-ISSTR)
  30       PARAMETER (MSCHR=-ISCHR)
  31       PARAMETER (MSBT2=-ISBT2)
  32       PARAMETER (MSTP2=-ISTP2)
  33       PARAMETER (MSW1=-ISW1)
  34       PARAMETER (MSW2=-ISW2)
  35       PARAMETER (MSNEL=-ISNEL)
  36       PARAMETER (MSEL=-ISEL)
  37       PARAMETER (MSNML=-ISNML)
  38       PARAMETER (MSMUL=-ISMUL)
  39       PARAMETER (MSNTL=-ISNTL)
  40       PARAMETER (MSTAU1=-ISTAU1)
  41       PARAMETER (MSER=-ISER)
  42       PARAMETER (MSMUR=-ISMUR)
  43       PARAMETER (MSTAU2=-ISTAU2)
  44       DIMENSION LISTJ(29)
  45       DATA LISTJ/9,1,-1,2,-2,3,-3,4,-4,5,-5,6,-6,
  46      111,-11,12,-12,13,-13,14,-14,15,-15,16,-16,10,80,-80,90/
  47       DATA IDSS/0,
  48      $ISUPL,MSUPL,ISDNL,MSDNL,ISSTL,MSSTL,ISCHL,MSCHL,ISBT1,MSBT1,
  49      $ISTP1,MSTP1,
  50      $ISUPR,MSUPR,ISDNR,MSDNR,ISSTR,MSSTR,ISCHR,MSCHR,ISBT2,MSBT2,
  51      $ISTP2,MSTP2,ISW1,MSW1,ISW2,MSW2,ISZ1,ISZ2,ISZ3,ISZ4,
  52      $ISNEL,MSNEL,ISEL,MSEL,ISNML,MSNML,ISMUL,MSMUL,
  53      $ISNTL,MSNTL,ISTAU1,MSTAU1,ISER,MSER,ISMUR,MSMUR,
  54      $ISTAU2,MSTAU2,
  55      $9,1,-1,2,-2,3,-3,4,-4,5,-5,6,-6,11,-11,12,-12,13,-13,
  56      $14,-14,15,-15,16,-16,10,80,-80,90,82,83,84,86,-86/
  57 C          ENTRY
  58       NPTCL=0
  59       NREJ=-1
  60       SIGMA=0.
  61       NSIGS=0
  62       DO 10 I=1,MXSIGS
  63 10    SIGS(I)=0.
  64       WT=1.
  65 C          GENERATE NEXT KINEMATIC POINT
  66 100   CONTINUE
  67       NREJ=NREJ+1
  68       IF(NREJ.GT.NTRIES) GO TO 9999
  69       NKINPT=NKINPT+1
  70       SUMWT=SUMWT+SIGMA*WT
  71       IF (IBREM) THEN
  72         RSH=RSHMIN+(RSHMAX-RSHMIN)*RANF()
  73         SHAT=RSH**2
  74         QSQ=SHAT
  75         XD=(1.-SHAT/SCM)*(-1.+2*RANF())
  76         X1=(XD+SQRT(XD**2+4*SHAT/SCM))/2.
  77         X2=X1-XD
  78       ELSE
  79         SHAT=SCM
  80         RSH=SQRT(SHAT)
  81       END IF
  82       PHI(1)=PHIMIN(1)+(PHIMAX(1)-PHIMIN(1))*RANF()
  83       PHI(2)=AMOD(PHI(1)+PI,2.*PI)
  84       CTH(1)=XJMIN(1)+(XJMAX(1)-XJMIN(1))*RANF()
  85       CTH(2)=-CTH(1)
  86       DO 110 I=1,2
  87       TH(I)=ACOS(CTH(I))
  88       STH(I)=SIN(TH(I))
  89       PT(I)=HALFE*STH(I)
  90       YJ(I)=.5*ALOG((1+CTH(I))/(1-CTH(I)))
  91       XJ(I)=CTH(I)
  92 110   CONTINUE
  93 C          CALCULATE CROSS SECTION
  94       IF (GOMSSM) THEN
  95         CALL SIGSSE
  96       ELSE
  97         CALL SIGEE
  98       END IF
  99       WT=XJMAX(1)-XJMIN(1)
 100 C          TEST CROSS SECTION
 101       IF(SIGMA.GT.SGMXEE) SGMXEE=SIGMA
 102       IF(SIGMA.LT.SGMXEE*RANF()) GO TO 100
 103       SUMWT=SUMWT+SIGMA*WT
 104       NKEEP=NKEEP+1
 105 C          SELECT JET TYPES
 106       SIGINV=1./SIGMA
 107       TRY=RANF()
 108       SUM=0.
 109       DO 200 I=1,NSIGS
 110       SUM=SUM+SIGS(I)*SIGINV
 111       IF(SUM.LT.TRY) GO TO 200
 112 C          FIND REACTION
 113       ISIGS=I
 114       SIGEVT=SIGS(ISIGS)
 115       II=INOUT(I)/IOPAK**2
 116       JETTYP(1)=MOD(II,IOPAK)
 117       II=II/IOPAK
 118       JETTYP(2)=MOD(II,IOPAK)
 119       GO TO 210
 120 200   CONTINUE
 121       GO TO 9998
 122 C          SET PJETS. RESET P AND PT INCLUDING MASSES.
 123 210   CONTINUE
 124       IF (GOMSSM) THEN
 125         AMQ(1)=AMASS(IDSS(JETTYP(1)))
 126         AMQ(2)=AMASS(IDSS(JETTYP(2)))
 127       ELSE
 128         AMQ(1)=AMASS(LISTJ(JETTYP(1)))
 129         AMQ(2)=AMASS(LISTJ(JETTYP(2)))
 130       END IF
 131       PCM=SQRT(SSXLAM(SHAT,AMQ(1)**2,AMQ(2)**2))/2./RSH
 132       DO 220 I=1,2
 133       PJETS(1,I)=PCM*STH(I)*COS(PHI(I))
 134       PJETS(2,I)=PCM*STH(I)*SIN(PHI(I))
 135       PJETS(3,I)=PCM*CTH(I)
 136       PJETS(4,I)=SQRT(PCM**2+AMQ(I)**2)
 137       PJETS(5,I)=AMQ(I)
 138       IF (GOMSSM) THEN
 139         IDJETS(I)=IDSS(JETTYP(I))
 140       ELSE
 141         IDJETS(I)=LISTJ(JETTYP(I))
 142       END IF
 143       P(I)=PCM
 144       PT(I)=P(I)*STH(I)
 145 220   CONTINUE
 146 C     IF BREMSSTRAHLUNG, THEN BOOST TO LAB FRAME
 147       IF (IBREM) THEN
 148         GAM=(X1+X2)*ECM/2./RSH
 149         V=-SIGN(1.,(X1-X2))*SQRT(ABS(1.-1./GAM)*(1.+1./GAM))
 150         DO I=1,2
 151           DUMMY=PJETS(4,I)
 152           PJETS(4,I)=GAM*(PJETS(4,I)-V*PJETS(3,I))
 153           PJETS(3,I)=GAM*(PJETS(3,I)-V*DUMMY)
 154         END DO
 155       END IF
 156       RETURN
 157 C          ERROR MESSAGES
 158 9998  CONTINUE
 159       CALL PRTEVT(0)
 160       WRITE(ITLIS,1010)
 161 1010  FORMAT(//' ERROR IN ELCTRN...NO GOOD JET TYPES FOUND')
 162       STOP 99
 163 9999  CONTINUE
 164       CALL PRTEVT(0)
 165       WRITE(ITLIS,1020) NTRIES
 166 1020  FORMAT(//' IT IS TAKING MORE THAN',I5,' TRIES TO GENERATE AN',
 167      $' EVENT. CHECK LIMITS OR INCREASE NTRIES.')
 168       STOP 99
 169       END