ISAJET/code/sighss.F

   1 #include "isajet/pilot.h"
   2       SUBROUTINE SIGHSS
   3 C
   4 C          Compute the integrated MSSM Higgs cross section
   5 C          d(sigma)/d(QMW**2)d(YW)
   6 C          Since SUSY Higgs are always narrow, can use the widths to
   7 C          determine couplings and ignore interference with continuum.
   8 C
   9 C          SIGMA    = cross section summed over quark types allowed by
  10 C                     JETTYPE and WTYPE cards.
  11 C          SIGS(I)  = partial cross section for I1 + I2 --> I3 + I4.
  12 C          INOUT(I) = IOPAK**3*I4 + IOPAK**2*I3 + IOPAK*I2 + I1
  13 C                     using JETTYPE code from LISTSS.
  14 C
  15 C          Ver 7.18: Correct GOQ's and include TBRWW for W/Z modes.
  16 C
  17 #if defined(CERNLIB_IMPNONE)
  18       IMPLICIT NONE
  19 #endif
  20 #include "isajet/itapes.inc"
  21 #include "isajet/qcdpar.inc"
  22 #include "isajet/jetpar.inc"
  23 #include "isajet/primar.inc"
  24 #include "isajet/q1q2.inc"
  25 #include "isajet/jetsig.inc"
  26 #include "isajet/qsave.inc"
  27 #include "isajet/wcon.inc"
  28 #include "isajet/const.inc"
  29 #include "isajet/jetlim.inc"
  30 #include "isajet/hcon.inc"
  31 C
  32       REAL X(2)
  33       REAL AMASS,STRUC
  34       REAL AM1,AM2,S,T,U,Q2SAVE,YHAT,EY,ANEFF,QMW2,QZW,EHAT,SIG0,SIG,
  35      $AMW
  36       INTEGER JT1,JT2,I,J,IH,IQ,I1,I2,JTGL,JTOFF
  37       EQUIVALENCE (S,SHAT),(T,THAT),(U,UHAT),(X(1),X1)
  38 C
  39 C          Kinematics (identical to Drell-Yan)
  40 C
  41       QMW2=QMW**2
  42       QTMW=SQRT(QMW2+QTW**2)
  43       Q0W=QTMW*COSH(YW)
  44       QZW=QTMW*SINH(YW)
  45       QW=SQRT(QZW**2+QTW**2)
  46       IF(QW.NE.0.) THEN
  47         CTHW=QZW/QW
  48         STHW=QTW/QW
  49         IF(ABS(CTHW).LT.1.) THEN
  50           THW=ACOS(CTHW)
  51         ELSE
  52           CTHW=0.
  53           STHW=1.
  54           THW=.5*PI
  55         ENDIF
  56       ELSE
  57         CTHW=0.
  58         STHW=1.
  59         THW=.5*PI
  60       ENDIF
  61       EHAT=QMW
  62       SHAT=QMW**2
  63       QSQ=SHAT
  64       ANEFF=4.+QSQ/(QSQ+AMASS(5)**2)+QSQ/(QSQ+AMASS(6)**2)
  65       ALFQSQ=12.*PI/((33.-ANEFF)*ALOG(QSQ/ALAM2))
  66       Q2SAVE=QSQ
  67       YHAT=YW
  68       EY=EXP(YHAT)
  69       X1=EHAT/ECM*EY
  70       X2=EHAT/(ECM*EY)
  71 C
  72 C          Initialize
  73 C
  74       SIGMA=0.
  75       NSIGS=0
  76       DO 100 I=1,MXSIGS
  77 100   SIGS(I)=0
  78       IF(X1.GE.1..OR.X2.GE.1.) RETURN
  79 C
  80 C          Compute structure functions
  81 C
  82       DO 110 IH=1,2
  83         DO 120 IQ=1,13
  84 120     QSAVE(IQ,IH)=STRUC(X(IH),QSQ,IQ,IDIN(IH))/X(IH)
  85         DO 130 IQ=14,26
  86 130     QSAVE(IQ,IH)=0.
  87 110   CONTINUE
  88 C
  89 C          gl + gl -> Higgs
  90 C
  91       JTGL=52
  92       SIG0=PI*HMASS**2/(8*S**2)*HGAMSS(JTGL,JTGL)*X1*X2*UNITS
  93      $/((S-HMASS**2)**2+(HMASS*HGAM)**2)
  94       SIG0=SIG0*QSAVE(1,1)*QSAVE(1,2)
  95       DO 200 I=1,85
  96         DO 210 J=1,85
  97           IF(HGAMSS(I,J).EQ.0) GO TO 210
  98           IF(.NOT.(GOQ(I,1).AND.GOQ(J,2))) GO TO 210
  99           SIG=SIG0*HGAMSS(I,J)
 100 C          Include W/Z branching ratios
 101           IF((I.GE.78.AND.I.LE.80).AND.(J.GE.78.AND.J.LE.80)) THEN
 102             SIG=SIG*TBRWW(I-76,1)*TBRWW(J-76,2)
 103           ENDIF
 104           CALL SIGFIL(SIG,JTGL,JTGL,I,J)
 105 210     CONTINUE
 106 200   CONTINUE
 107 C
 108 C          qk + qb -> Higgs
 109 C
 110       JTOFF=51
 111 C          Note I1,I2 run over quarks; JT1,JT2,I,J over LISTSS
 112       DO 300 I1=2,13
 113         AM1=AMASS(I1/2)
 114         JT1=I1+JTOFF
 115         DO 310 I2=2,13
 116           AM2=AMASS(I2/2)
 117           JT2=I2+JTOFF
 118           IF(HGAMSS(JT1,JT2).LE.0) GO TO 310
 119           SIG0=4*PI*HMASS**2/(9*S**2)*HGAMSS(JT1,JT2)*X1*X2*UNITS
 120      $    /((S-HMASS**2)**2+(HMASS*HGAM)**2)
 121           SIG0=SIG0*QSAVE(I1,1)*QSAVE(I2,2)
 122 C          Decay partial cross sections
 123           DO 320 I=1,85
 124             DO 330 J=1,85
 125               IF(HGAMSS(I,J).EQ.0) GO TO 330
 126               IF(.NOT.(GOQ(I,1).AND.GOQ(J,2))) GO TO 330
 127               SIG=SIG0*HGAMSS(I,J)
 128 C          Include W/Z branching ratios
 129               IF((I.GE.78.AND.I.LE.80).AND.(J.GE.78.AND.J.LE.80)) THEN
 130                 SIG=SIG*TBRWW(I-76,1)*TBRWW(J-76,2)
 131               ENDIF
 132               CALL SIGFIL(SIG,JT1,JT2,I,J)
 133 330         CONTINUE
 134 320       CONTINUE
 135 310     CONTINUE
 136 300   CONTINUE
 137 C
 138       RETURN
 139       END