HIJING/hijing1_36/g.F

   1 * $Id$
   2 C
   3 C
   4 C
   5 C
   6         FUNCTION G(Y1,Y2,PT2)
   7         IMPLICIT REAL*8 (A-H,O-Z)
   8 #include "hiparnt.inc"
   9         DIMENSION F(2,7)
  10         SAVE
  11         XT=2.0*DSQRT(PT2)/HINT1(1)
  12         X1=0.50*XT*(DEXP(Y1)+DEXP(Y2))
  13         X2=0.50*XT*(DEXP(-Y1)+DEXP(-Y2))
  14         DUMMY = 1.D0-XT**2/X1/X2
  15         if (DUMMY.LT.0.D0) DUMMY = 0.D0
  16         Z=DSQRT(DUMMY)
  17         SS=X1*X2*HINT1(1)**2
  18         T=-(1.0-Z)/2.0
  19         U=-(1.0+Z)/2.0
  20         AF=3.0
  21         DLAM=HIPR1(15)
  22         APH=12.0*3.1415926/(33.0-2.0*AF)/DLOG(PT2/DLAM**2)
  23 C
  24         CALL PARTON(F,X1,X2,PT2)
  25 C
  26         G11=( (F(1,1)+F(1,2))*(F(2,3)+F(2,4)+F(2,5)+F(2,6))
  27      &      +(F(1,3)+F(1,4))*(F(2,5)+F(2,6)) )*SUBCRS1(T,U)
  28 C
  29         G12=( (F(2,1)+F(2,2))*(F(1,3)+F(1,4)+F(1,5)+F(1,6))
  30      &      +(F(2,3)+F(2,4))*(F(1,5)+F(1,6)) )*SUBCRS1(U,T)
  31 C
  32         G13=(F(1,1)*F(2,1)+F(1,2)*F(2,2)+F(1,3)*F(2,3)+F(1,4)*F(2,4)
  33      &      +F(1,5)*F(2,5)+F(1,6)*F(2,6))*(SUBCRS1(U,T)
  34      &      +SUBCRS1(T,U)-8.D0/T/U/27.D0)
  35 C
  36         G2=(AF-1)*(F(1,1)*F(2,2)+F(2,1)*F(1,2)+F(1,3)*F(2,4)
  37      &     +F(2,3)*F(1,4)+F(1,5)*F(2,6)+F(2,5)*F(1,6))*SUBCRS2(T,U)
  38 C
  39         G31=(F(1,1)*F(2,2)+F(1,3)*F(2,4)+F(1,5)*F(2,6))*SUBCRS3(T,U)
  40         G32=(F(2,1)*F(1,2)+F(2,3)*F(1,4)+F(2,5)*F(1,6))*SUBCRS3(U,T)
  41 C
  42         G4=(F(1,1)*F(2,2)+F(2,1)*F(1,2)+F(1,3)*F(2,4)+F(2,3)*F(1,4)+
  43      1  F(1,5)*F(2,6)+F(2,5)*F(1,6))*SUBCRS4(T,U)
  44 C
  45         G5=AF*F(1,7)*F(2,7)*SUBCRS5(T,U)
  46 C
  47         G61=F(1,7)*(F(2,1)+F(2,2)+F(2,3)+F(2,4)+F(2,5)
  48      &      +F(2,6))*SUBCRS6(T,U)
  49         G62=F(2,7)*(F(1,1)+F(1,2)+F(1,3)+F(1,4)+F(1,5)
  50      &      +F(1,6))*SUBCRS6(U,T)
  51 C
  52         G7=F(1,7)*F(2,7)*SUBCRS7(T,U)
  53 C
  54         G=(G11+G12+G13+G2+G31+G32+G4+G5+G61+G62+G7)*HIPR1(17)*
  55      1  3.14159D0*APH**2/SS**2
  56         RETURN
  57         END