ISAJET/code/zjj.F

   1 #include "isajet/pilot.h"
   2       SUBROUTINE ZJJ
   3 C-----------------------------------------------------------------------
   4 C
   5 C          Use MadGraph/Helas to generate Z + 2 jets after setup by
   6 C          ZJJ0 using cross section routines from MadGraph:
   7 C          ZJJ1:   q1 q1b -> Z q2 q2b, q1 != q2
   8 C          ZJJ2:   g  g   -> Z q2 q2b
   9 C          ZJJ3:   q1 q1b -> Z g  g
  10 C          ZJJ4:   q1 q1b -> Z q1 q1b
  11 C          ZJJ5:   q1 q2  -> Z q1 q2
  12 C          ZJJ6:   q1 q1  -> Z q1 q1
  13 C          ZJJ7:   g  q   -> Z g  q
  14 C
  15 C          Note: The Z is always jet1, but the other two jets are
  16 C          symmetrized so a symmetry factor of 1/2 is needed for every
  17 C          subprocess. This is included by MadGraph for identical
  18 C          particles!
  19 C
  20 C-----------------------------------------------------------------------
  21 #if defined(CERNLIB_IMPNONE)
  22       IMPLICIT NONE
  23 #endif
  24 #include "isajet/const.inc"
  25 #include "isajet/q1q2.inc"
  26 #include "isajet/itapes.inc"
  27 #include "isajet/jetlim.inc"
  28 #include "isajet/jetpar.inc"
  29 #include "isajet/jetset.inc"
  30 #include "isajet/partcl.inc"
  31 #include "isajet/pinits.inc"
  32 #include "isajet/pjets.inc"
  33 #include "isajet/primar.inc"
  34 #include "isajet/sstype.inc"
  35 #include "isajet/totals.inc"
  36 #include "isajet/mgkin.inc"
  37 #include "isajet/mgcoms.inc"
  38 #include "isajet/mgsigs.inc"
  39 C
  40       INTEGER IMAD(6)
  41       REAL*8 P1(0:3),P2(0:3),P3(0:3),P4(0:3),P5(0:3)
  42       EQUIVALENCE (P1(0),PJETS8(0,1))
  43       EQUIVALENCE (P2(0),PJETS8(0,2))
  44       EQUIVALENCE (P3(0),PJETS8(0,3))
  45       EQUIVALENCE (P4(0),PJETS8(0,4))
  46       EQUIVALENCE (P5(0),PJETS8(0,5))
  47       REAL QFCN,XX,QQ,RND,RANF,SIG,FJAC,STRUC,ALQCD
  48       REAL*8 SZJJ1,WT8,TERM,SUM,SZJJ2,SZJJ3,SZJJ4,SIG8,SIGI8
  49       REAL*8 SZJJ5,SZJJ6,SZJJ7
  50       INTEGER IQ,IH,ISIG8,IFL1,IFL2,IM1,IM2,IQ1,IQ2,NTRY,I,II,K,IWT8
  51 C
  52 C          Map Jettype/2 to MadGraph
  53       DATA IMAD/3,4,8,7,12,11/
  54 C
  55 C          Parton distributions
  56       QFCN(XX,IQ,IH)=STRUC(XX,QQ,IQ,IDIN(IH))/XX
  57 C
  58 C          Begin
  59 C
  60       NTRY=0
  61       NJSET=0
  62       NPTCL=0
  63 C
  64 C          Select process
  65 C
  66       RND=RANF()
  67       ISIG8=0
  68       SIG=0
  69       DO 10 I=1,NSIG8
  70         SIG=SIG+WTSUM8(I)/NWT8(I)
  71 10    CONTINUE
  72       SUM=0
  73       DO 20 I=1,NSIG8
  74         II=ISORT8(NSIG8+1-I)
  75         SUM=SUM+WTSUM8(II)/NWT8(II)
  76         IF(SUM.GE.RND*SIG) THEN
  77           ISIG8=II
  78           GO TO 100
  79         ENDIF
  80 20    CONTINUE
  81       WRITE(ITLIS,*) 'ERROR IN ZJJ: NO MODE FOUND'
  82       STOP99
  83 C
  84 100   CONTINUE
  85       SIG8=0
  86       FJAC=UNITS/SCM
  87       NTRY=NTRY+1
  88       IF(NTRY.GT.NTRIES) THEN
  89         WRITE(ITLIS,*) 'ERROR IN ZJJ: NTRY = ',NTRY
  90         WRITE(ITLIS,*) 'PROCESS WAS ',(IDENT8(K,ISIG8),K=1,5)
  91         SIGI8=WTSUM8(ISIG8)/NWT8(ISIG8)
  92         WRITE(ITLIS,*) 'PROCESS SIGMA/MAX = ',SIGI8,WTMAX8(ISIG8)
  93         WRITE(ITLIS,*) 'CHECK YOUR LIMITS OR INCREASE NTRIES'
  94         STOP99
  95       ENDIF
  96 C
  97 C          Cases 1,4: q1 q1b -> z q2 q2b
  98 C
  99       IF(IFUNC8(ISIG8).EQ.1.OR.IFUNC8(ISIG8).EQ.4) THEN
 100         AMJET8(3)=ZMASS
 101         IFL1=IABS(IDENT8(1,ISIG8))
 102         IM1=IMAD(IFL1)
 103         IQ1=2*IFL1
 104         IQ2=IQ1+1
 105         AMJET8(1)=FMASS(IM1)
 106         AMJET8(2)=FMASS(IM1)
 107         IFL2=IABS(IDENT8(4,ISIG8))
 108         IM2=IMAD(IFL2)
 109         AMJET8(4)=FMASS(IM2)
 110         AMJET8(5)=FMASS(IM2)
 111         DO 210 I=1,NTRIES
 112           IWT8=I
 113           CALL MULJET(WT8)
 114           IF(WT8.GT.0) GO TO 220
 115 210     CONTINUE
 116         WRITE(ITLIS,*) 'ERROR IN ZJJ: NO PHASE SPACE POINT IN ',
 117      $  NTRIES,' TRIES'
 118         STOP99
 119 220     NWTTOT=NWTTOT+IWT8-1
 120         NWT8(ISIG8)=NWT8(ISIG8)+IWT8-1
 121         X1=(P1(0)+P1(3))/ECM
 122         X2=(P2(0)-P2(3))/ECM
 123         QQ=P3(1)**2+P3(2)**2+P4(1)**2+P4(2)**2+P5(1)**2+
 124      $  P5(2)**2+AMJET8(3)**2+AMJET8(4)**2+AMJET8(5)**2
 125 C
 126 C          Subcases
 127 C
 128         IF(IDENT8(1,ISIG8).GT.0.AND.IDENT8(4,ISIG8).GT.0) THEN
 129           IF(IFUNC8(ISIG8).EQ.1) THEN
 130             TERM=SZJJ1(P1,P2,P3,P4,P5,IM1,IM2)
 131           ELSE
 132             TERM=SZJJ4(P1,P2,P3,P4,P5,IM1)
 133           ENDIF
 134           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 135           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 136         ELSEIF(IDENT8(1,ISIG8).GT.0.AND.IDENT8(4,ISIG8).LT.0) THEN
 137           IF(IFUNC8(ISIG8).EQ.1) THEN
 138             TERM=SZJJ1(P1,P2,P3,P5,P4,IM1,IM2)
 139           ELSE
 140             TERM=SZJJ4(P1,P2,P3,P5,P4,IM1)
 141           ENDIF
 142           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 143           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 144         ELSEIF(IDENT8(1,ISIG8).LT.0.AND.IDENT8(4,ISIG8).GT.0) THEN
 145           IF(IFUNC8(ISIG8).EQ.1) THEN
 146             TERM=SZJJ1(P1,P2,P3,P4,P5,IM1,IM2)
 147           ELSE
 148             TERM=SZJJ4(P1,P2,P3,P4,P5,IM1)
 149           ENDIF
 150           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 151           TERM=TERM*WT8*FJAC*QFCN(X1,IQ2,1)*QFCN(X2,IQ1,2)
 152         ELSEIF(IDENT8(1,ISIG8).LT.0.AND.IDENT8(4,ISIG8).LT.0) THEN
 153           IF(IFUNC8(ISIG8).EQ.1) THEN
 154             TERM=SZJJ1(P1,P2,P3,P5,P4,IM1,IM2)
 155           ELSE
 156             TERM=SZJJ4(P1,P2,P3,P5,P4,IM1)
 157           ENDIF
 158           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 159           TERM=TERM*WT8*FJAC*QFCN(X1,IQ2,1)*QFCN(X2,IQ1,2)
 160         ELSE
 161           WRITE(ITLIS,*) 'ERROR IN ZJJ...INVALID FLAVOR FOR ZJJ1'
 162           STOP99
 163         ENDIF
 164         SIG8=0.5*TERM
 165         GO TO 900
 166       ENDIF
 167 C
 168 C          Case 2: g g -> z q2 q2b
 169 C
 170       IF(IFUNC8(ISIG8).EQ.2) THEN
 171         AMJET8(3)=ZMASS
 172         IFL1=IABS(IDENT8(1,ISIG8))
 173         AMJET8(1)=0
 174         AMJET8(2)=0
 175         IFL2=IABS(IDENT8(4,ISIG8))
 176         IM2=IMAD(IFL2)
 177         AMJET8(4)=FMASS(IM2)
 178         AMJET8(5)=FMASS(IM2)
 179         DO 310 I=1,NTRIES
 180           IWT8=I
 181           CALL MULJET(WT8)
 182           IF(WT8.GT.0) GO TO 320
 183 310     CONTINUE
 184         WRITE(ITLIS,*) 'ERROR IN ZJJ: NO PHASE SPACE POINT IN ',
 185      $  NTRIES,' TRIES'
 186         STOP99
 187 320     NWTTOT=NWTTOT+IWT8-1
 188         NWT8(ISIG8)=NWT8(ISIG8)+IWT8-1
 189         X1=(P1(0)+P1(3))/ECM
 190         X2=(P2(0)-P2(3))/ECM
 191         QQ=P3(1)**2+P3(2)**2+P4(1)**2+P4(2)**2+P5(1)**2+
 192      $  P5(2)**2+AMJET8(3)**2+AMJET8(4)**2+AMJET8(5)**2
 193 C
 194 C          Subcases
 195 C
 196         IF(IDENT8(4,ISIG8).GT.0) THEN
 197           TERM=SZJJ2(P1,P2,P3,P4,P5,IM2)
 198           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 199           TERM=TERM*WT8*FJAC*QFCN(X1,1,1)*QFCN(X2,1,2)
 200         ELSEIF(IDENT8(4,ISIG8).LT.0) THEN
 201           TERM=SZJJ2(P1,P2,P3,P5,P4,IM2)
 202           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 203           TERM=TERM*WT8*FJAC*QFCN(X1,1,1)*QFCN(X2,1,2)
 204         ELSE
 205           WRITE(ITLIS,*) 'ERROR IN ZJJ...INVALID FLAVOR FOR ZJJ2'
 206           STOP99
 207         ENDIF
 208         SIG8=0.5*TERM
 209         GO TO 900
 210       ENDIF
 211 C
 212 C          Case 3: q1 q1b -> z g g
 213 C
 214       IF(IFUNC8(ISIG8).EQ.3) THEN
 215         AMJET8(3)=ZMASS
 216         IFL1=IABS(IDENT8(1,ISIG8))
 217         IQ1=2*IFL1
 218         IQ2=IQ1+1
 219         IM1=IMAD(IFL1)
 220         AMJET8(1)=FMASS(IM1)
 221         AMJET8(2)=FMASS(IM1)
 222         IFL2=9
 223         AMJET8(4)=0
 224         AMJET8(5)=0
 225         DO 410 I=1,NTRIES
 226           IWT8=I
 227           CALL MULJET(WT8)
 228           IF(WT8.GT.0) GO TO 420
 229 410     CONTINUE
 230         WRITE(ITLIS,*) 'ERROR IN ZJJ: NO PHASE SPACE POINT IN ',
 231      $  NTRIES,' TRIES'
 232         STOP99
 233 420     NWTTOT=NWTTOT+IWT8-1
 234         NWT8(ISIG8)=NWT8(ISIG8)+IWT8-1
 235         X1=(P1(0)+P1(3))/ECM
 236         X2=(P2(0)-P2(3))/ECM
 237         QQ=P3(1)**2+P3(2)**2+P4(1)**2+P4(2)**2+P5(1)**2+
 238      $  P5(2)**2+AMJET8(3)**2+AMJET8(4)**2+AMJET8(5)**2
 239 C
 240 C          Subcases
 241 C
 242         IF(IDENT8(1,ISIG8).GT.0) THEN
 243           TERM=SZJJ3(P1,P2,P3,P4,P5,IM1)
 244           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 245           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 246         ELSEIF(IDENT8(1,ISIG8).LT.0) THEN
 247           TERM=SZJJ3(P2,P1,P3,P4,P5,IM1)
 248           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 249           TERM=TERM*WT8*FJAC*QFCN(X1,IQ2,1)*QFCN(X2,IQ1,2)
 250         ELSE
 251           WRITE(ITLIS,*) 'ERROR IN ZJJ...INVALID FLAVOR FOR ZJJ3'
 252           STOP99
 253         ENDIF
 254         SIG8=TERM
 255         GO TO 900
 256       ENDIF
 257 C
 258 C          Cases 5,6: q1 q2 -> z q1 q2
 259 C
 260       IF(IFUNC8(ISIG8).EQ.5.OR.IFUNC8(ISIG8).EQ.6) THEN
 261         IFL1=IABS(IDENT8(1,ISIG8))
 262         IM1=IMAD(IFL1)
 263         IFL2=IABS(IDENT8(2,ISIG8))
 264         IM2=IMAD(IFL2)
 265         IQ1=2*IFL1
 266         IQ2=2*IFL2
 267         IF(IDENT8(1,ISIG8).LT.0) IQ1=IQ1+1
 268         IF(IDENT8(2,ISIG8).LT.0) IQ2=IQ2+1
 269         AMJET8(1)=FMASS(IM1)
 270         AMJET8(2)=FMASS(IM2)
 271         AMJET8(3)=ZMASS
 272         AMJET8(4)=FMASS(IM1)
 273         AMJET8(5)=FMASS(IM2)
 274         DO 510 I=1,NTRIES
 275           IWT8=I
 276           CALL MULJET(WT8)
 277           IF(WT8.GT.0) GO TO 520
 278 510     CONTINUE
 279         WRITE(ITLIS,*) 'ERROR IN ZJJ: NO PHASE SPACE POINT IN ',
 280      $  NTRIES,' TRIES'
 281         STOP99
 282 520     NWTTOT=NWTTOT+IWT8-1
 283         NWT8(ISIG8)=NWT8(ISIG8)+IWT8-1
 284         X1=(P1(0)+P1(3))/ECM
 285         X2=(P2(0)-P2(3))/ECM
 286         QQ=P3(1)**2+P3(2)**2+P4(1)**2+P4(2)**2+P5(1)**2+
 287      $  P5(2)**2+AMJET8(3)**2+AMJET8(4)**2+AMJET8(5)**2
 288 C
 289 C          Subcases
 290 C
 291         IF(IDENT8(1,ISIG8).EQ.IDENT8(4,ISIG8)) THEN
 292           IF(IFUNC8(ISIG8).EQ.5) THEN
 293             TERM=SZJJ5(P1,P2,P3,P4,P5,IM1,IM2)
 294           ELSE
 295             TERM=SZJJ6(P1,P2,P3,P4,P5,IM1)
 296           ENDIF
 297           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 298           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 299         ELSEIF(IDENT8(1,ISIG8).EQ.IDENT8(5,ISIG8)) THEN
 300           TERM=SZJJ5(P1,P2,P3,P5,P4,IM1,IM2)
 301           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 302           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 303         ELSE
 304           WRITE(ITLIS,*) 'ERROR IN ZJJ...INVALID FLAVOR FOR ZJJ1'
 305           STOP99
 306         ENDIF
 307         SIG8=TERM
 308         IF(IFL1.NE.IFL2) SIG8=0.5*SIG8
 309         GO TO 900
 310       ENDIF
 311 C
 312 C          Case 7: g q -> z g q
 313 C
 314       IF(IFUNC8(ISIG8).EQ.7) THEN
 315         IF(IDENT8(1,ISIG8).EQ.9) THEN
 316           IFL1=IABS(IDENT8(2,ISIG8))
 317           IM1=IMAD(IFL1)
 318           AMJET8(1)=0
 319           AMJET8(2)=FMASS(IM1)
 320           IQ1=1
 321           IQ2=2*IFL1
 322           IF(IDENT8(2,ISIG8).LT.0) IQ2=IQ2+1
 323         ELSE
 324           IFL1=IABS(IDENT8(1,ISIG8))
 325           IM1=IMAD(IFL1)
 326           AMJET8(1)=FMASS(IM1)
 327           AMJET8(2)=0
 328           IQ2=1
 329           IQ1=2*IFL1
 330           IF(IDENT8(1,ISIG8).LT.0) IQ1=IQ1+1
 331         ENDIF
 332         AMJET8(3)=ZMASS
 333         IF(IDENT8(4,ISIG8).EQ.9) THEN
 334           AMJET8(4)=0
 335           AMJET8(5)=FMASS(IM1)
 336         ELSE
 337           AMJET8(4)=FMASS(IM1)
 338           AMJET8(5)=0
 339         ENDIF
 340         DO 610 I=1,NTRIES
 341           IWT8=I
 342           CALL MULJET(WT8)
 343           IF(WT8.GT.0) GO TO 620
 344 610     CONTINUE
 345         WRITE(ITLIS,*) 'ERROR IN ZJJ: NO PHASE SPACE POINT IN ',
 346      $  NTRIES,' TRIES'
 347         STOP99
 348 620     NWTTOT=NWTTOT+IWT8-1
 349         NWT8(ISIG8)=NWT8(ISIG8)+IWT8-1
 350         X1=(P1(0)+P1(3))/ECM
 351         X2=(P2(0)-P2(3))/ECM
 352         QQ=P3(1)**2+P3(2)**2+P4(1)**2+P4(2)**2+P5(1)**2+
 353      $  P5(2)**2+AMJET8(3)**2+AMJET8(4)**2+AMJET8(5)**2
 354 C
 355 C          Subcases
 356 C
 357         IF(IDENT8(1,ISIG8).EQ.9.AND.IDENT8(4,ISIG8).EQ.9) THEN
 358           TERM=SZJJ7(P1,P2,P3,P4,P5,IM1)
 359           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 360           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 361         ELSEIF(IDENT8(2,ISIG8).EQ.9.AND.IDENT8(4,ISIG8).EQ.9) THEN
 362           TERM=SZJJ7(P2,P1,P3,P4,P5,IM1)
 363           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 364           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 365         ELSEIF(IDENT8(1,ISIG8).EQ.9.AND.IDENT8(5,ISIG8).EQ.9) THEN
 366           TERM=SZJJ7(P1,P2,P3,P5,P4,IM1)
 367           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 368           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 369         ELSEIF(IDENT8(2,ISIG8).EQ.9.AND.IDENT8(5,ISIG8).EQ.9) THEN
 370           TERM=SZJJ7(P2,P1,P3,P5,P4,IM1)
 371           TERM=TERM*(4*PI*ALQCD(REAL(QQ)))**2
 372           TERM=TERM*WT8*FJAC*QFCN(X1,IQ1,1)*QFCN(X2,IQ2,2)
 373         ELSE
 374           WRITE(ITLIS,*) 'ERROR IN ZJJ...INVALID FLAVOR FOR ZJJ1'
 375           STOP99
 376         ENDIF
 377         SIG8=0.5*TERM
 378         GO TO 900
 379       ENDIF
 380 C
 381 C          Increment totals and test
 382 C
 383 900   WTTOT8=WTTOT8+SIG8
 384       NWTTOT=NWTTOT+1
 385       WTSUM8(ISIG8)=WTSUM8(ISIG8)+SIG8
 386       WTMAX8(ISIG8)=MAX(WTMAX8(ISIG8),SIG8)
 387       NWT8(ISIG8)=NWT8(ISIG8)+1
 388       IF(SIG8.LT.RANF()*WTMAX8(ISIG8)) GO TO 100
 389 C
 390 C          Good event
 391 C
 392       DO 910 I=1,3
 393         DO 911 K=1,3
 394           PJETS(K,I)=PJETS8(K,I+2)
 395 911     CONTINUE
 396         PJETS(4,I)=PJETS8(0,I+2)
 397         PJETS(5,I)=AMJET8(I+2)
 398         IDJETS(I)=IDENT8(I+2,ISIG8)
 399 910   CONTINUE
 400       DO 920 I=1,2
 401         DO 921 K=1,3
 402           PINITS(K,I)=PJETS8(K,I)
 403 921     CONTINUE
 404         PINITS(4,I)=PJETS8(0,I)
 405         PINITS(5,I)=AMJET8(I)
 406         IDINIT(I)=IDENT8(I,ISIG8)
 407 920   CONTINUE
 408 C
 409       QSQ=QQ
 410       SHAT=(P1(0)+P2(0))**2-(P1(3)+P2(3))**2
 411       PBEAM(1)=(1.-X1)*HALFE
 412       PBEAM(2)=(1.-X2)*HALFE
 413 C
 414 C          Set /TOTALS/
 415 C
 416       NKINPT=NWTTOT
 417       SUMWT=WTTOT8
 418 C
 419       RETURN
 420       END