Adding macros to create Calibration objects
[u/mrichter/AliRoot.git] / HIJING / hijing1_36 / ghvq.F
1 * $Id$
2 C
3 C
4 C
5         FUNCTION GHVQ(Y1,Y2,AMT2)
6         IMPLICIT REAL*8 (A-H,O-Z)
7 #define BLANKET_SAVE
8 #include "hiparnt.inc"
9         DIMENSION F(2,7)
10         SAVE
11         XT=2.0*DSQRT(AMT2)/HINT1(1)
12         X1=0.50*XT*(DEXP(Y1)+DEXP(Y2))
13         X2=0.50*XT*(DEXP(-Y1)+DEXP(-Y2))
14         SS=X1*X2*HINT1(1)**2
15         AF=4.0
16         IF(IHPR2(18).NE.0) AF=5.0
17         DLAM=HIPR1(15)
18         APH=12.0*3.1415926/(33.0-2.0*AF)/DLOG(AMT2/DLAM**2)
19 C
20         CALL PARTON(F,X1,X2,AMT2)
21 C
22         Gqq=4.0*(COSH(Y1-Y2)+HIPR1(7)**2/AMT2)/(1.D0+COSH(Y1-Y2))/9.0
23      &      *(F(1,1)*F(2,2)+F(1,2)*F(2,1)+F(1,3)*F(2,4)
24      &        +F(1,4)*F(2,3)+F(1,5)*F(2,6)+F(1,6)*F(2,5))
25         Ggg=(8.D0*COSH(Y1-Y2)-1.D0)*(COSH(Y1-Y2)+2.0*HIPR1(7)**2/AMT2
26      &      -2.0*HIPR1(7)**4/AMT2**2)/(1.0+COSH(Y1-Y2))/24.D0
27      &      *F(1,7)*F(2,7)
28 C
29         GHVQ=(Gqq+Ggg)*HIPR1(23)*3.14159*APH**2/SS**2
30         RETURN
31         END