ISAJET/code/sigtc3.F

   1 #include "isajet/pilot.h"
   2       SUBROUTINE SIGTC3
   3 C
   4 C          Calculate angular distributions for W decays from technirho:
   5 C          d(sigma)/d(qmw**2)d(yw)d(omega)d(omega1)d(omega2)
   6 C
   7 #if defined(CERNLIB_IMPNONE)
   8       IMPLICIT NONE
   9 #endif
  10 C
  11 #include "isajet/itapes.inc"
  12 #include "isajet/qcdpar.inc"
  13 #include "isajet/jetpar.inc"
  14 #include "isajet/pjets.inc"
  15 #include "isajet/primar.inc"
  16 #include "isajet/q1q2.inc"
  17 #include "isajet/jetsig.inc"
  18 #include "isajet/wsig.inc"
  19 #include "isajet/wwsig.inc"
  20 #include "isajet/wcon.inc"
  21 #include "isajet/const.inc"
  22 #include "isajet/wwpar.inc"
  23 #include "isajet/tcpar.inc"
  24 C
  25       EQUIVALENCE (S,SHAT),(T,THAT),(U,UHAT)
  26       INTEGER I,K,IDADDR(4),IW(2)
  27       REAL T12(3,3),T34(3,3),FR(3,3),FI(3,3),CPHI12(3),SPHI12(3),
  28      $CPHI34(3),SPHI34(3),PFCM(5,4),PWCM(5,2),CHWW,SHWW,TMP,PTW1,
  29      $CPHIW1,SPHIW1,PW1,CTHW1,STHW1,CHW1,SHW1,SHWI,TH12,PHI12,TH34,
  30      $PHI34,AMV,GAMV,QMH,A12,B12,A34,B34,TVV12,TVA12,COS12,SIN12,
  31      $TVV34,TVA34,COS34,SIN34,TCPHI,TSPHI,TC2PHI,TS2PHI,F0,F1,TOTAL,
  32      $DIFF,T,U,S
  33 C
  34       IF(NPAIR.NE.4) RETURN
  35 C
  36 C          Reconstruct W-->FF decay angles
  37 C
  38 C          Initialize PFCM and PWCM
  39       DO 10 I=1,4
  40       DO 10 K=1,5
  41         PFCM(K,I)=PPAIR(K,I)
  42 10    CONTINUE
  43       DO 11 I=1,2
  44       DO 11 K=1,5
  45         PWCM(K,I)=PJETS(K,I)
  46 11    CONTINUE
  47 C
  48 C          Z boost to WW center of mass
  49       CHWW=QWJET(4)/QWJET(5)
  50       SHWW=QWJET(3)/QWJET(5)
  51       DO 20 I=1,4
  52         TMP=CHWW*PFCM(4,I)-SHWW*PFCM(3,I)
  53         PFCM(3,I)=-SHWW*PFCM(4,I)+CHWW*PFCM(3,I)
  54         PFCM(4,I)=TMP
  55 20    CONTINUE
  56       DO 21 I=1,2
  57         TMP=CHWW*PWCM(4,I)-SHWW*PWCM(3,I)
  58         PWCM(3,I)=-SHWW*PWCM(4,I)+CHWW*PWCM(3,I)
  59         PWCM(4,I)=TMP
  60 21    CONTINUE
  61 C
  62 C          Rotate W1 to +z axis
  63       PTW1=SQRT(PWCM(1,1)**2+PWCM(2,1)**2)
  64       CPHIW1=PWCM(1,1)/PTW1
  65       SPHIW1=PWCM(2,1)/PTW1
  66       PW1=SQRT(PTW1**2+PWCM(3,1)**2)
  67       CTHW1=PWCM(3,1)/PW1
  68       STHW1=PTW1/PW1
  69 C          Z rotation
  70       DO 30 I=1,4
  71         TMP=CPHIW1*PFCM(1,I)+SPHIW1*PFCM(2,I)
  72         PFCM(2,I)=-SPHIW1*PFCM(1,I)+CPHIW1*PFCM(2,I)
  73         PFCM(1,I)=TMP
  74 30    CONTINUE
  75 C          Y rotation
  76       DO 31 I=1,4
  77         TMP=CTHW1*PFCM(1,I)-STHW1*PFCM(3,I)
  78         PFCM(3,I)=STHW1*PFCM(1,I)+CTHW1*PFCM(3,I)
  79         PFCM(1,I)=TMP
  80 31    CONTINUE
  81 C
  82 C          Boost to W rest frames
  83       CHW1=PWCM(4,1)/PWCM(5,1)
  84       SHW1=PW1/PWCM(5,1)
  85       DO 40 I=1,4
  86         IF(I.LE.2) THEN
  87           SHWI=SHW1
  88         ELSE
  89           SHWI=-SHW1
  90         ENDIF
  91         TMP=CHW1*PFCM(4,I)-SHWI*PFCM(3,I)
  92         PFCM(3,I)=-SHWI*PFCM(4,I)+CHW1*PFCM(3,I)
  93         PFCM(4,I)=TMP
  94 40    CONTINUE
  95 C
  96 C          Compute angles
  97       TH12=ACOS(PFCM(3,1)/SQRT(PFCM(1,1)**2+PFCM(2,1)**2+PFCM(3,1)**2))
  98       PHI12=ATAN2(PFCM(2,1),PFCM(1,1))
  99       TH34=ACOS(PFCM(3,3)/SQRT(PFCM(1,3)**2+PFCM(2,3)**2+PFCM(3,3)**2))
 100       PHI34=ATAN2(PFCM(2,3),PFCM(1,3))
 101 C
 102 C          Compute decay angular distributions.
 103 C
 104       DO 100 I=1,4
 105         IDADDR(I)=IABS(IDPAIR(I))
 106         IF(IDADDR(I).GE.11) IDADDR(I)=IDADDR(I)-4
 107 100   CONTINUE
 108       IW(1)=JETTYP(1)-25
 109       IW(2)=JETTYP(2)-25
 110 C
 111       AMV=PJETS(5,1)
 112       GAMV=WGAM(IW(1))
 113       QMH=QMW
 114 C          COUPLINGS
 115       A12=AQ(IDADDR(1),IW(1))
 116       B12=BQ(IDADDR(1),IW(1))
 117       A34=AQ(IDADDR(3),IW(2))
 118       B34=BQ(IDADDR(3),IW(2))
 119 C          DECAY DISTRIBUTIONS
 120       TVV12=8.*PI*ALFA*(A12**2+B12**2)
 121       TVA12=16.*PI*ALFA*A12*B12
 122       COS12=COS(TH12)
 123       SIN12=SIN(TH12)
 124       T12(1,1)=TVV12*SIN12**2
 125       T12(1,2)=TVV12*SIN12*COS12/SQRT2+TVA12*SIN12/SQRT2
 126       T12(1,3)=-TVV12*SIN12*COS12/SQRT2+TVA12*SIN12/SQRT2
 127       T12(2,1)=T12(1,2)
 128       T12(2,2)=TVV12*(.5+.5*COS12**2)+TVA12*COS12
 129       T12(2,3)=TVV12*.5*SIN12**2
 130       T12(3,1)=T12(1,3)
 131       T12(3,2)=T12(2,3)
 132       T12(3,3)=TVV12*(.5+.5*COS12**2)-TVA12*COS12
 133 C
 134       TVV34=8.*PI*ALFA*(A34**2+B34**2)
 135       TVA34=16.*PI*ALFA*A34*B34
 136       COS34=COS(TH34)
 137       SIN34=SIN(TH34)
 138       T34(1,1)=TVV34*SIN34**2
 139       T34(1,2)=TVV34*SIN34*COS34/SQRT2+TVA34*SIN34/SQRT2
 140       T34(1,3)=-TVV34*SIN34*COS34/SQRT2+TVA34*SIN34/SQRT2
 141       T34(2,1)=T34(1,2)
 142       T34(2,2)=TVV34*(.5+.5*COS34**2)+TVA34*COS34
 143       T34(2,3)=TVV34*.5*SIN34**2
 144       T34(3,1)=T34(1,3)
 145       T34(3,2)=T34(2,3)
 146       T34(3,3)=TVV34*(.5+.5*COS34**2)-TVA34*COS34
 147 C
 148       CPHI12(1)=1.
 149       CPHI12(2)=COS(PHI12)
 150       CPHI12(3)=COS(2.*PHI12)
 151       SPHI12(1)=0.
 152       SPHI12(2)=SIN(PHI12)
 153       SPHI12(3)=SIN(2.*PHI12)
 154       CPHI34(1)=1.
 155       CPHI34(2)=COS(PHI34)
 156       CPHI34(3)=COS(2.*PHI34)
 157       SPHI34(1)=0.
 158       SPHI34(2)=SIN(PHI34)
 159       SPHI34(3)=SIN(2.*PHI34)
 160 C
 161       TCPHI=CPHI12(2)*CPHI34(2)-SPHI12(2)*SPHI34(2)
 162       TSPHI=SPHI12(2)*CPHI34(2)+CPHI12(2)*SPHI34(2)
 163       TC2PHI=CPHI12(3)*CPHI34(3)-SPHI12(3)*SPHI34(3)
 164       TS2PHI=SPHI12(3)*CPHI34(3)+CPHI12(3)*SPHI34(3)
 165 C
 166 C          Pure technirho --> WW. Calculate angular distribution for
 167 C          decay and multiply by cross section.
 168 C
 169       F0=.5*QMH**2/AMV**2-1.
 170       F1=1.
 171       TOTAL=(8.*PI/3.)**2*TVV12*TVV34*(F0**2+2.*F1**2)
 172       DIFF=F0**2*T12(1,1)*T34(1,1)
 173      $+F0*F1*(2.*T12(1,2)*T34(1,2)+2.*T12(1,3)*T34(1,3))*TCPHI
 174      $+F1**2*(T12(2,2)*T34(1,2)+T12(3,3)*T34(3,3)
 175      $  +2.*T12(2,3)*T34(2,3)*TC2PHI)
 176       WWSIG=SIGLLQ*DIFF/TOTAL
 177       RETURN
 178       END