2 C-----------------------------------------------------------------------
3 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
5 * G R S - LO - VIRTUAL PHOTON PARAMETRIZATIONS *
7 * FOR A DETAILED EXPLANATION SEE *
8 * M. GLUECK, E.REYA, M. STRATMANN : *
9 * PHYS. REV. D51 (1995) 3220 *
11 * THE PARAMETRIZATIONS ARE FITTED TO THE EVOLVED PARTONS FOR *
12 * Q**2 / GEV**2 BETWEEN 0.6 AND 5.E4 *
13 * AND (!) Q**2 > 5 P**2 *
14 * P**2 / GEV**2 BETWEEN 0.0 AND 10. *
15 * P**2 = 0 <=> REAL PHOTON *
16 * X BETWEEN 1.E-4 AND 1. *
18 * HEAVY QUARK THRESHOLDS Q(H) = M(H) IN THE BETA FUNCTION : *
19 * M(C) = 1.5, M(B) = 4.5 *
20 * CORRESPONDING LAMBDA(F) VALUES IN GEV FOR Q**2 > M(H)**2 : *
21 * LO : LAMBDA(3) = 0.232, LAMBDA(4) = 0.200, *
22 * LAMBDA(5) = 0.153, *
23 * THE NUMBER OF ACTIVE QUARK FLAVOURS IS NF = 3 EVERYWHERE *
24 * EXCEPT IN THE BETA FUNCTION, I.E. THE HEAVY QUARKS C,B,... *
25 * ARE NOT PRESENT AS PARTONS IN THE Q2-EVOLUTION. *
27 * PLEASE REPORT ANY STRANGE BEHAVIOUR TO : *
28 * STRAT@HAL1.PHYSIK.UNI-DORTMUND.DE *
29 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
31 *...INPUT PARAMETERS :
33 * X = MOMENTUM FRACTION
34 * Q2 = SCALE Q**2 IN GEV**2
35 * P2 = VIRTUALITY OF THE PHOTON IN GEV**2
37 *...OUTPUT (ALWAYS X TIMES THE DISTRIBUTION DIVIDED BY ALPHA_EM) :
38 *...OUTPUT (ALWAYS X TIMES THE DISTRIBUTION) : modified H.P.-B. 10.9.1996
40 ********************************************************
41 SUBROUTINE GRSGALO(DX,DQ2,DP2,
42 + DUPV,DDNV,DUSEA,DDSEA,DSTR,DCHM,DBOT,DGL)
43 C subroutine grsgalo(x,q2,p2,ugam,dgam,sgam,ggam)
44 #include "pdf/impdp.inc"
45 #if defined(CERNLIB_DOUBLE)
48 #if defined(CERNLIB_SINGLE)
51 + x, q2, p2, mu2, lam2,
52 + ugam, dgam, sgam, ggam,
53 + DUPV,DDNV,DUSEA,DDSEA,DSTR,DCHM,DBOT,DGL
55 dimension u1(40),ds1(40),g1(40)
56 dimension ud2(20),s2(20),g2(20)
57 dimension up0(20),dsp0(20),gp0(20)
58 DATA ALPHEM/7.29927D-3/
60 data u1/-0.139d0,0.783d0,0.132d0,0.087d0,0.003d0,-0.0134d0,
61 + 0.009d0,-0.017d0,0.092d0,-0.516d0,-0.085d0,0.439d0,
62 + 0.013d0,0.108d0,-0.019d0,-0.272d0,-0.167d0,0.138d0,
63 + 0.076d0,0.026d0,-0.013d0,0.27d0,0.107d0,-0.097d0,0.04d0,
64 + 0.064d0,0.011d0,0.002d0,0.057d0,-0.057d0,0.162d0,
65 + -0.172d0,0.124d0,-0.016d0,-0.065d0,0.044d0,-1.009d0,
66 + 0.622d0,0.227d0,-0.184d0/
67 data ds1/0.033d0,0.007d0,-0.0516d0,0.12d0,0.001d0,-0.013d0,
68 + 0.018d0,-0.028d0,0.102d0,-0.595d0,-0.114d0,0.669d0,
69 + 0.022d0,0.001d0,-0.003d0,-0.0583d0,-0.041d0,0.035d0,
70 + 0.009d0,0.009d0,0.004d0,0.054d0,0.025d0,-0.02d0,
71 + 0.007d0,0.021d0,0.01d0,0.004d0,-0.067d0,0.06d0,-0.148d0,
72 + 0.13d0,0.032d0,-0.009d0,-0.06d0,0.036d0,-0.39d0,0.033d0,
74 data g1/0.025d0,0.d0,-0.018d0,0.112d0,-0.025d0,0.177d0,
75 + -0.022d0,0.024d0,0.001d0,-0.0104d0,0.d0,0.d0,-1.082d0,
76 + -1.666d0,0.d0,0.086d0,0.d0,0.053d0,0.005d0,-0.058d0,
77 + 0.034d0,0.073d0,1.08d0,1.63d0,-0.0256d0,-0.088d0,0.d0,
78 + 0.d0,-0.004d0,0.016d0,0.007d0,-0.012d0,0.01d0,-0.673d0,
79 + 0.126d0,-0.167d0,0.032d0,-0.227d0,0.086d0,-0.159d0/
80 data ud2/0.756d0,0.187d0,0.109d0,-0.163d0,0.002d0,0.004d0,
81 + 0.054d0,-0.039d0,22.53d0,-21.02d0,5.608d0,0.332d0,
82 + -0.008d0,-0.021d0,0.381d0,0.572d0,4.774d0,1.436d0,
84 data s2/0.902d0,0.182d0,0.271d0,-0.346d0,0.017d0,-0.01d0,
85 + -0.011d0,0.0065d0,17.1d0,-13.29d0,6.519d0,0.031d0,
86 + -0.0176d0,0.003d0,1.243d0,0.804d0,4.709d0,1.499d0,
88 data g2/0.364d0,1.31d0,0.86d0,-0.254d0,0.611d0,0.008d0,
89 + -0.097d0,-2.412d0,-0.843d0,2.248d0,-0.201d0,1.33d0,
90 + 0.572d0,0.44d0,1.233d0,0.009d0,0.954d0,1.862d0,3.791d0,
92 data up0/1.551d0,0.105d0,1.089d0,-0.172d0,3.822d0,-2.162d0,
93 + 0.533d0,-0.467d0,-0.412d0,0.2d0,0.377d0,0.299d0,0.487d0,
94 + 0.0766d0,0.119d0,0.063d0,7.605d0,0.234d0,-0.567d0,
96 data dsp0/2.484d0,1.214d0,1.088d0,-0.1735d0,4.293d0,
97 + -2.802d0,0.5975d0,-0.1193d0,-0.0872d0,0.0418d0,0.128d0,
98 + 0.0337d0,0.127d0,0.0135d0,0.14d0,0.0423d0,6.946d0,
99 + 0.814d0,1.531d0,0.124d0/
100 data gp0/1.682d0,1.1d0,0.5888d0,-0.4714d0,0.5362d0,0.0127d0,
101 + -2.438d0,0.03399d0,0.07825d0,0.05842d0,0.08393d0,2.348d0,
102 + -0.07182d0,1.084d0,0.3098d0,-0.07514d0,3.327d0,1.1d0,
105 save u1,ds1,g1,ud2,s2,g2,up0,dsp0,gp0
114 if(p2.le.0.25d0) then
115 s=log(log(q2/lam2)/log(mu2/lam2))
122 + (' WARNING: GRSGALO has been called with Q2 < P2 !',/,
123 + ' GRSGALO is about to blow up, therefore',/,
124 + ' Q2 is set equal to P2')
127 s=log(log(q2/lam2)/log(p2/lam2))
128 lp1=log(p2/mu2)*log(p2/mu2)
129 lp2=log(p2/mu2+log(p2/mu2))
132 alp=up0(1)+lp1*u1(1)+lp2*u1(2)
133 bet=up0(2)+lp1*u1(3)+lp2*u1(4)
134 a=up0(3)+lp1*u1(5)+lp2*u1(6)+
135 + (up0(4)+lp1*u1(7)+lp2*u1(8))*s
136 b=up0(5)+lp1*u1(9)+lp2*u1(10)+
137 + (up0(6)+lp1*u1(11)+lp2*u1(12))*s**0.5+
138 + (up0(7)+lp1*u1(13)+lp2*u1(14))*s**2
139 gb=up0(8)+lp1*u1(15)+lp2*u1(16)+
140 + (up0(9)+lp1*u1(17)+lp2*u1(18))*s+
141 + (up0(10)+lp1*u1(19)+lp2*u1(20))*s**2
142 ga=up0(11)+lp1*u1(21)+lp2*u1(22)+
143 + (up0(12)+lp1*u1(23)+lp2*u1(24))*s**0.5
144 gc=up0(13)+lp1*u1(25)+lp2*u1(33)+
145 + (up0(14)+lp1*u1(26)+lp2*u1(34))*s
146 gd=up0(15)+lp1*u1(27)+lp2*u1(35)+
147 + (up0(16)+lp1*u1(28)+lp2*u1(36))*s
148 ge=up0(17)+lp1*u1(29)+lp2*u1(37)+
149 + (up0(18)+lp1*u1(30)+lp2*u1(38))*s
150 gep=up0(19)+lp1*u1(31)+lp2*u1(39)+
151 + (up0(20)+lp1*u1(32)+lp2*u1(40))*s
152 upart1=grsf2(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)
154 alp=dsp0(1)+lp1*ds1(1)+lp2*ds1(2)
155 bet=dsp0(2)+lp1*ds1(3)+lp2*ds1(4)
156 a=dsp0(3)+lp1*ds1(5)+lp2*ds1(6)+
157 + (dsp0(4)+lp1*ds1(7)+lp2*ds1(8))*s
158 b=dsp0(5)+lp1*ds1(9)+lp2*ds1(10)+
159 + (dsp0(6)+lp1*ds1(11)+lp2*ds1(12))*s**0.5+
160 + (dsp0(7)+lp1*ds1(13)+lp2*ds1(14))*s**2
161 gb=dsp0(8)+lp1*ds1(15)+lp2*ds1(16)+
162 + (dsp0(9)+lp1*ds1(17)+lp2*ds1(18))*s+
163 + (dsp0(10)+lp1*ds1(19)+lp2*ds1(20))*s**2
164 ga=dsp0(11)+lp1*ds1(21)+lp2*ds1(22)+
165 + (dsp0(12)+lp1*ds1(23)+lp2*ds1(24))*s
166 gc=dsp0(13)+lp1*ds1(25)+lp2*ds1(33)+
167 + (dsp0(14)+lp1*ds1(26)+lp2*ds1(34))*s
168 gd=dsp0(15)+lp1*ds1(27)+lp2*ds1(35)+
169 + (dsp0(16)+lp1*ds1(28)+lp2*ds1(36))*s
170 ge=dsp0(17)+lp1*ds1(29)+lp2*ds1(37)+
171 + (dsp0(18)+lp1*ds1(30)+lp2*ds1(38))*s
172 gep=dsp0(19)+lp1*ds1(31)+lp2*ds1(39)+
173 + (dsp0(20)+lp1*ds1(32)+lp2*ds1(40))*s
174 dspart1=grsf2(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)
176 alp=gp0(1)+lp1*g1(1)+lp2*g1(2)
177 bet=gp0(2)+lp1*g1(3)+lp2*g1(4)
178 a=gp0(3)+lp1*g1(5)+lp2*g1(6)+
179 + (gp0(4)+lp1*g1(7)+lp2*g1(8))*s**0.5
180 b=gp0(5)+lp1*g1(9)+lp2*g1(10)+
181 + (gp0(6)+lp1*g1(11)+lp2*g1(12))*s**2
182 gb=gp0(7)+lp1*g1(13)+lp2*g1(14)+
183 + (gp0(8)+lp1*g1(15)+lp2*g1(16))*s
184 ga=gp0(9)+lp1*g1(17)+lp2*g1(18)+
185 + (gp0(10)+lp1*g1(19)+lp2*g1(20))*s**0.5+
186 + (gp0(11)+lp1*g1(21)+lp2*g1(22))*s**2
187 gc=gp0(12)+lp1*g1(23)+lp2*g1(24)+
188 + (gp0(13)+lp1*g1(25)+lp2*g1(26))*s**2
189 gd=gp0(14)+lp1*g1(27)+lp2*g1(28)+
190 + (gp0(15)+lp1*g1(29)+lp2*g1(30))*s+
191 + (gp0(16)+lp1*g1(31)+lp2*g1(32))*s**2
192 ge=gp0(17)+lp1*g1(33)+lp2*g1(34)+
193 + (gp0(18)+lp1*g1(35)+lp2*g1(36))*s
194 gep=gp0(19)+lp1*g1(37)+lp2*g1(38)+
195 + (gp0(20)+lp1*g1(39)+lp2*g1(40))*s
196 gpart1=grsf2(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)
198 s=log(log(q2/lam2)/log(mu2/lam2))
199 suppr=1.d0/(1.d0+p2/0.59d0)**2
204 ga=ud2(5)+ud2(6)*s**0.5
206 b=ud2(9)+ud2(10)*s+ud2(11)*s**2
207 gb=ud2(12)+ud2(13)*s+ud2(14)*s**2
210 gep=ud2(19)+ud2(20)*s
211 udpart2=suppr*grsf1(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)
216 ga=s2(5)+s2(6)*s**0.5
218 b=s2(9)+s2(10)*s+s2(11)*s**2
219 gb=s2(12)+s2(13)*s+s2(14)*s**2
223 spart2=suppr*grsf2(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)
230 ga=g2(9)+g2(10)*s**0.5+g2(11)*s**2
231 gc=g2(12)+g2(13)*s**2
232 gd=g2(14)+g2(15)*s+g2(16)*s**2
235 gpart2=suppr*grsf1(x,s,alp,bet,a,b,ga,gb,gc,gd,ge,gep)