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g.f
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file g.f
1 C
2 C
3 C
4 C
5  FUNCTION g(Y1,Y2,PT2)
6  IMPLICIT REAL*8 (a-h,o-z)
7  REAL hipr1(100),hint1(100)
8  common/hiparnt/hipr1,ihpr2(50),hint1,ihnt2(50)
9  SAVE /hiparnt/
10  dimension f(2,7)
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  z=dsqrt(1.d0-xt**2/x1/x2)
15  ss=x1*x2*hint1(1)**2
16  t=-(1.0-z)/2.0
17  u=-(1.0+z)/2.0
18  af=3.0
19  dlam=hipr1(15)
20  aph=12.0*3.1415926/(33.0-2.0*af)/dlog(pt2/dlam**2)
21 C
22  CALL parton(f,x1,x2,pt2)
23 C
24  g11=( (f(1,1)+f(1,2))*(f(2,3)+f(2,4)+f(2,5)+f(2,6))
25  & +(f(1,3)+f(1,4))*(f(2,5)+f(2,6)) )*subcrs1(t,u)
26 C
27  g12=( (f(2,1)+f(2,2))*(f(1,3)+f(1,4)+f(1,5)+f(1,6))
28  & +(f(2,3)+f(2,4))*(f(1,5)+f(1,6)) )*subcrs1(u,t)
29 C
30  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)
31  & +f(1,5)*f(2,5)+f(1,6)*f(2,6))*(subcrs1(u,t)
32  & +subcrs1(t,u)-8.d0/t/u/27.d0)
33 C
34  g2=(af-1)*(f(1,1)*f(2,2)+f(2,1)*f(1,2)+f(1,3)*f(2,4)
35  & +f(2,3)*f(1,4)+f(1,5)*f(2,6)+f(2,5)*f(1,6))*subcrs2(t,u)
36 C
37  g31=(f(1,1)*f(2,2)+f(1,3)*f(2,4)+f(1,5)*f(2,6))*subcrs3(t,u)
38  g32=(f(2,1)*f(1,2)+f(2,3)*f(1,4)+f(2,5)*f(1,6))*subcrs3(u,t)
39 C
40  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)+
41  1 f(1,5)*f(2,6)+f(2,5)*f(1,6))*subcrs4(t,u)
42 C
43  g5=af*f(1,7)*f(2,7)*subcrs5(t,u)
44 C
45  g61=f(1,7)*(f(2,1)+f(2,2)+f(2,3)+f(2,4)+f(2,5)
46  & +f(2,6))*subcrs6(t,u)
47  g62=f(2,7)*(f(1,1)+f(1,2)+f(1,3)+f(1,4)+f(1,5)
48  & +f(1,6))*subcrs6(u,t)
49 C
50  g7=f(1,7)*f(2,7)*subcrs7(t,u)
51 C
52  g=(g11+g12+g13+g2+g31+g32+g4+g5+g61+g62+g7)*hipr1(17)*
53  1 3.14159d0*aph**2/ss**2
54 
55  RETURN
56  END