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pygrvd.f
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1 
2 C*********************************************************************
3 
4 C...PYGRVD
5 C...Gives the GRV 94 D (DIS) parton distribution function set
6 C...in parametrized form.
7 C...Authors: M. Glueck, E. Reya and A. Vogt.
8 
9  SUBROUTINE pygrvd (X, Q2, UV, DV, DEL, UDB, SB, CHM, BOT, GL)
10 
11 C...Double precision declaration.
12  IMPLICIT DOUBLE PRECISION (a - z)
13 
14 C...Common expressions.
15  mu2 = 0.34d0
16  lam2 = 0.248d0 * 0.248d0
17  s = log(log(q2/lam2) / log(mu2/lam2))
18  ds = sqrt(s)
19  s2 = s * s
20  s3 = s2 * s
21 
22 C...uv :
23  nu = 2.484d0 + 0.116d0 * s + 0.093d0 * s2
24  aku = 0.563d0 - 0.025d0 * s
25  bku = 0.054d0 + 0.154d0 * s
26  au = -0.326d0 - 0.058d0 * s - 0.135d0 * s2
27  bu = -3.322d0 + 8.259d0 * s - 3.119d0 * s2 + 0.291d0 * s3
28  cu = 11.52d0 - 12.99d0 * s + 3.161d0 * s2
29  du = 2.808d0 + 1.400d0 * s - 0.557d0 * s2 + 0.119d0 * s3
30  uv = pygrvv(x, nu, aku, bku, au, bu, cu, du)
31 
32 C...dv :
33  nd = 0.156d0 - 0.017d0 * s
34  akd = 0.299d0 - 0.022d0 * s
35  bkd = 0.259d0 - 0.015d0 * s
36  ad = 3.445d0 + 1.278d0 * s + 0.326d0 * s2
37  bd = -6.934d0 + 37.45d0 * s - 18.95d0 * s2 + 1.463d0 * s3
38  cd = 55.45d0 - 69.92d0 * s + 20.78d0 * s2
39  dd = 3.577d0 + 1.441d0 * s - 0.683d0 * s2 + 0.179d0 * s3
40  dv = pygrvv(x, nd, akd, bkd, ad, bd, cd, dd)
41 
42 C...del :
43  ne = 0.099d0 + 0.019d0 * s + 0.002d0 * s2
44  ake = 0.419d0 - 0.013d0 * s
45  bke = 1.064d0 - 0.038d0 * s
46  ae = -44.00d0 + 98.70d0 * s - 14.79d0 * s2
47  be = 28.59d0 - 40.94d0 * s - 13.66d0 * s2 + 2.523d0 * s3
48  ce = 84.57d0 - 108.8d0 * s + 31.52d0 * s2
49  de = 7.469d0 + 2.480d0 * s - 0.866d0 * s2
50  del = pygrvv(x, ne, ake, bke, ae, be, ce, de)
51 
52 C...udb :
53  alx = 1.215d0
54  bex = 0.466d0
55  akx = 0.326d0 + 0.150d0 * s
56  bkx = 0.956d0 + 0.405d0 * s
57  agx = 0.272d0
58  bgx = 3.794d0 - 2.359d0 * ds
59  cx = 2.014d0
60  dx = 7.941d0 + 0.534d0 * ds - 0.940d0 * s + 0.410d0 * s2
61  ex = 3.049d0 + 1.597d0 * s
62  esx = 4.396d0 - 4.594d0 * ds + 3.268d0 * s
63  udb = pygrvw(x, s, alx, bex, akx, bkx, agx, bgx, cx,
64  & dx, ex, esx)
65 
66 C...sb :
67  sts = 0d0
68  als = 0.175d0
69  bes = 0.344d0
70  aks = 1.415d0 - 0.641d0 * ds
71  as = 0.580d0 - 9.763d0 * ds + 6.795d0 * s - 0.558d0 * s2
72  bs = 5.617d0 + 5.709d0 * ds - 3.972d0 * s
73  dst = 13.78d0 - 9.581d0 * s + 5.370d0 * s2 - 0.996d0 * s3
74  est = 4.546d0 + 0.372d0 * s2
75  ess = 5.053d0 - 1.070d0 * s + 0.805d0 * s2
76  sb = pygrvs(x, s, sts, als, bes, aks, as, bs, dst, est, ess)
77 
78 C...cb :
79  stc = 0.820d0
80  alc = 0.98d0
81  bec = 0d0
82  akc = -0.625d0 - 0.523d0 * s
83  ac = 0d0
84  bc = 1.896d0 + 1.616d0 * s
85  dct = 4.12d0 + 0.683d0 * s
86  ect = 4.36d0 + 1.328d0 * s
87  esc = 0.677d0 + 0.679d0 * s
88  chm = pygrvs(x, s, stc, alc, bec, akc, ac, bc, dct, ect, esc)
89 
90 C...bb :
91  stb = 1.297d0
92  alb = 0.99d0
93  beb = 0d0
94  akb = - 0.193d0 * s
95  ab = 0d0
96  bb = 0d0
97  dbt = 3.447d0 + 0.927d0 * s
98  ebt = 4.68d0 + 1.259d0 * s
99  esb = 1.892d0 + 2.199d0 * s
100  bot = pygrvs(x, s, stb, alb, beb, akb, ab, bb, dbt, ebt, esb)
101 
102 C...gl :
103  alg = 1.258d0
104  beg = 1.846d0
105  akg = 2.423d0
106  bkg = 2.427d0 + 1.311d0 * s - 0.153d0 * s2
107  ag = 25.09d0 - 7.935d0 * s
108  bg = -14.84d0 - 124.3d0 * ds + 72.18d0 * s
109  cg = 590.3d0 - 173.8d0 * s
110  dg = 5.196d0 + 1.857d0 * s
111  eg = -1.648d0 + 3.988d0 * s - 0.432d0 * s2
112  esg = 3.232d0 - 0.542d0 * s
113  gl = pygrvw(x, s, alg, beg, akg, bkg, ag, bg, cg, dg, eg, esg)
114 
115  RETURN
116  END