5 * Revision 1.1.1.2 1996/10/30 08:30:46 cernlib
8 * Revision 1.1.1.1 1996/04/12 15:29:46 plothow
12 #include "pdf/pilot.h"
13 c-------------------------------------------------------
14 subroutine SFWHI6(ZX,ZQ,ZUV,ZDV,ZUB,ZDB,ZSB,ZCB,ZGL)
15 c-------------------------------------------------------
16 c WHIT6 parton distribution in the photon
18 c INPUT: integer ic : if ic=0 then qc=0
19 c else qc is calculated
20 c DOUBLE PRECISION Q2 : energy scale Q^2 (GeV^2)
21 c DOUBLE PRECISION x : energy fraction
23 c OUTPUT: DOUBLE PRECISION qu : up-quark dist.
24 c DOUBLE PRECISION qd : down- or strange-quark dist.
25 c DOUBLE PRECISION qc : charm-quark dist.
26 c DOUBLE PRECISION g : gluon dist.
27 c-------------------------------------------------------
28 c Modified by M.Tanaka on July 22, 1994.
29 c The bug pointed out by M.Drees is fixed.
30 c-------------------------------------------------------
31 c Modified by I.Watanabe on July 22, 1994.
32 c-------------------------------------------------------
35 #include "pdf/expdp.inc"
36 + ZX,ZQ,ZUV,ZDV,ZUB,ZDB,ZSB,ZCB,ZGL
40 DOUBLE PRECISION qu,qd,qc,g
42 DOUBLE PRECISION q42it,q52it,lam42,lam52
43 DOUBLE PRECISION alinv,mc,PI
45 DOUBLE PRECISION qv,qsea,cv,cs,dcv,dcs
46 DOUBLE PRECISION A0val,A1val,A2val,Bval,Cval,
47 $ A0sea,B0sea,BB0sea,C0sea
48 DOUBLE PRECISION A0dcv,A1dcv,A2dcv,A3dcv,Bdcv,Cdcv
49 DOUBLE PRECISION Adcs, B0dcs, B1dcs, Cdcs
50 DOUBLE PRECISION x1,x2,mc2q2
51 DOUBLE PRECISION s,s2,s3,s4,prsccf,alstpi
52 DOUBLE PRECISION WHIT6G
54 parameter(lam42=0.16d0, lam52=0.091411319d0)
55 parameter(Q42IT=4.0d0, Q52IT=100.0d0)
56 parameter(alinv=137.036d0, mc=1.5d0)
57 parameter(pi=3.14159265358979323846d0)
58 common /scale/ s,s2,s3,s4,prsccf
69 if(Q2.lt.100.0d0) then
74 cccc for under 4GeV^2 prescription
76 prsccf = log(Q2/LAM42)/ log(Q42IT/LAM42)
77 alstpi = 6.0d0/25.0d0/ log(Q42IT/LAM42)
79 s= log( log(Q2/LAM42)/ log(Q42IT/LAM42))
81 alstpi = 6.0d0/25.0d0/ log(Q2/LAM42)
87 cccccc WHIT6 quark (U100)
89 A0val= 2.540000d+00+s*( 2.000000d+00)+s2*( 7.180000d-01)
90 A1val= 6.230000d-02+s*(-7.010000d+00)+s2*( 1.251000d-01)
91 A2val=-1.642000d-01+s*(-4.360000d-01)+s2*( 1.048000d+01)
93 Bval = 6.990000d-01+s*(-2.796000d-02)+s2*(-3.650000d-03)
94 Cval = 4.420000d-01+s*(-1.255000d+00)+s2*( 1.941000d+00)
96 A0sea= 3.180000d+00+s*( 8.690000d+00)+s2*(-2.287000d+01)
97 $ +s3*( 1.896000d+01)+s4*(-5.140000d+00)
98 B0sea=-1.003000d-01+s*( 1.603000d-01)+s2*(-1.037000d+00)
99 $ +s3*( 9.440000d-01)+s4*(-2.915000d-01)
100 BB0sea=5.690000d+00+s*( 1.867000d+01)+s2*(-4.670000d+01)
101 $ +s3*( 5.050000d+01)+s4*(-1.835000d+01)
102 C0sea= 2.149000d+01+s*(-5.650000d+01)+s2*( 1.293000d+02)
103 $ +s3*(-1.459000d+02)+s4*( 5.750000d+01)
106 $ (A0val+A1val*x+A2val*x2) * x**Bval * x1**Cval
107 qsea= prsccf/alinv/x*
108 $ A0sea * x**(B0sea+BB0sea*x) * x1**C0sea
110 qu = qv/3.0d0 + qsea/6.0d0
114 qd = qv/12.0d0 + qsea/6.0d0
120 if((ic.ne.0) .and. (x*(1.0d0+4.0d0*mc2q2).lt.1.0d0)) then
121 call WHIT6Q(x,mc2q2,cv,cs)
122 qc = cv/alinv/2.0d0/PI + cs*alstpi
138 s= log( log(Q2/LAM52)/ log(Q52IT/LAM52))
140 alstpi = 6.0d0/23.0d0/ log(Q2/LAM52)
145 cccccc WHIT6 quark (O100)
147 A0val= 4.270000d+00+s*( 3.096000d+00)+s2*( 1.621000d+00)
148 A1val=-4.740000d+00+s*(-6.900000d+00)+s2*(-2.439000d+00)
149 A2val= 2.837000d+00+s*( 6.460000d+00)+s2*( 4.100000d+00)
150 Bval = 6.780000d-01+s*(-3.940000d-02)+s2*( 1.758000d-02)
151 Cval = 1.728000d-01+s*(-2.493000d-02)+s2*( 1.451000d-01)
152 A0sea= 3.340000d+00+s*(-5.610000d+00)+s2*( 5.000000d+01)
153 $ +s3*(-2.207000d+02)+s4*( 3.028000d+02)
154 B0sea=-2.402000d-01+s*(-4.090000d-01)+s2*( 2.263000d+00)
155 $ +s3*(-1.050000d+01)+s4*( 1.487000d+01)
156 BB0sea=8.790000d+00+s*(-8.860000d+00)+s2*( 1.640000d+02)
157 $ +s3*(-7.120000d+02)+s4*( 9.730000d+02)
158 C0sea= 9.160000d+00+s*( 9.290000d+00)+s2*(-2.784000d+02)
159 $ +s3*( 1.175000d+03)+s4*(-1.592000d+03)
162 $ (A0val+A1val*x+A2val*x2) * x**Bval * x1**Cval
164 $ A0sea * x**(B0sea+BB0sea*x) * x1**C0sea
166 qu = qv/3.0d0 + qsea/6.0d0
170 qd = qv/12.0d0 + qsea/6.0d0
179 if((ic.ne.0) .and. (x*(1.0d0+4.0d0*mc2q2).lt.1.0d0)) then
180 A0dcv= s*( 1.219000d-01)+s2*( 6.200000d+00)
181 $ +s3*(-2.504000d+01)+s4*( 3.098000d+01)
182 A1dcv= s*( 1.913000d+00)+s2*(-7.690000d+01)
183 $ +s3*( 3.180000d+02)+s4*(-3.920000d+02)
184 A2dcv= s*(-7.160000d+00)+s2*( 2.503000d+02)
185 $ +s3*(-1.062000d+03)+s4*( 1.308000d+03)
186 A3dcv= s*( 3.190000d+00)+s2*(-2.301000d+02)
187 $ +s3*( 1.012000d+03)+s4*(-1.250000d+03)
188 Bdcv = 4.990000d-01+s*( 3.470000d+00)+s2*(-1.526000d+01)
189 $ +s3*( 1.967000d+01)
190 Cdcv = 3.290000d-01+s*( 8.240000d+00)+s2*(-3.800000d+01)
191 $ +s3*( 4.630000d+01)
192 Adcs = s*(-4.990000d-02)+s2*( 1.026000d-01)
193 $ +s3*(-7.870000d-02)
194 B0dcs=-3.610000d-01+s*(-5.760000d-01)+s2*( 2.257000d-01)
195 B1dcs= 7.680000d+00+s*(-8.830000d+00)+s2*( 3.880000d+00)
196 Cdcs = 2.548000d+00+s*( 6.910000d-01)+s2*(-8.700000d+00)
197 $ +s3*( 1.065000d+01)
200 $ (A0dcv+x*A1dcv+x2*A2dcv+x2*x*A3dcv) * x**Bdcv * x1**Cdcv
202 $ Adcs * x**(B0dcs+B1dcs*x) * x1**Cdcs
204 call WHIT6Q(x,mc*mc/Q2,cv,cs)
205 qc = cv/alinv/2.0d0/PI + cs*alstpi + dcs + dcv