5 * Revision 1.1.1.2 1996/10/30 08:28:02 cernlib
8 * Revision 1.1.1.1 1996/04/12 15:29:15 plothow
12 #include "pdf/pilot.h"
13 SUBROUTINE DGPHO1(DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL)
14 C********************************************************************
16 C* Parametrization of parton distribution functions *
17 C* in the photon (LO analysis) - full solution of AP eq.! *
19 C* authors: M.Drees and K.Grassie (DG) *
20 C* /Z. Phys. C28 (1985) 451/ *
23 C* Krzysztof Charchula, DESY *
24 C* bitnet: F1PCHA@DHHDESY3 *
25 C* decnet: 13313::CHARCHULA *
28 C* H. Plothow-Besch/CERN-PPE *
30 C********************************************************************
32 #include "pdf/impdp.inc"
33 #include "pdf/expdp.inc"
35 + B(5,4,2,3),BT(5,2),XQPOM(2),E(2),
36 + DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL
37 PARAMETER (ALPEM=7.29927D-3, PI=3.141592D0)
38 PARAMETER (ALAM=0.4D0)
40 C...--------------------------------------------------
41 C... nf=3 for 1< Q2 <32 GeV2
42 C... nf=4 for 32< Q2 <200 GeV2
43 C... nf=5 for 200< Q2 <1D4 GeV2
44 C...--------------------------------------------------
46 C...initialization of gluon parameters array for DG
47 DATA (((A(I,J,K),I=1,3),J=1,4),K=1,3)/
48 > -0.20700, -0.19870, 5.1190,
49 > 0.61580, 0.62570, -0.2752,
50 > 1.07400, 8.35200, -6.9930,
51 > 0.00000, 5.02400, 2.2980,
52 > 0.8926D-2,0.0509, -0.2313,
53 > 0.65940, 0.27740, 0.1382,
54 > 0.47660, -0.39060, 6.5420,
55 > 0.01975, -0.32120, 0.5162,
56 > 0.03197, -0.618D-2,-0.1216,
57 > 1.01800, 0.94760, 0.9047,
58 > 0.24610, -0.60940, 2.6530,
59 > 0.02707, -0.01067, 0.2003D-2/
61 C...initialization of quark parameters array for DG
62 DATA (((B(I,J,K,1),I=1,5),J=1,4),K=1,2)/
63 > 2.2850, 6.0730, -0.4202, -0.0808, 0.0553,
64 > -0.0153, -0.8132, 0.0178, 0.6346, 1.1360,
65 > 1.33D3, -41.310, 0.9216, 1.2080, 0.9512,
66 > 4.2190, 3.1650, 0.1800, 0.2030, 0.0116,
67 > 16.690, 0.1760, -0.0208, -0.0168, -0.1986,
68 > -0.7916, 0.0479, 0.3386D-2, 1.3530, 1.1000,
69 > 1.0990D3, 1.0470, 4.8530, 1.4260, 1.1360,
70 > 4.4280, 0.0250, 0.8404, 1.2390, -0.2779/
71 DATA (((B(I,J,K,2),I=1,5),J=1,4),K=1,2)/
72 > -0.3711, -0.1717, 0.08766, -0.8915, -0.1816,
73 > 1.0610, 0.7815, 0.02197, 0.2857, 0.5866,
74 > 4.7580, 1.5350, 0.10960, 2.9730, 2.4210,
75 > -0.0150, 0.7067D-2,0.20400, 0.1185, 0.4059,
76 > -0.1207, 25.000, -0.01230, -0.0919, 0.02015,
77 > 1.0710, -1.6480, 1.16200, 0.7912, 0.9869,
78 > 1.9770, -0.01563, 0.48240, 0.6397, -0.07036,
79 > -0.8625D-2,6.4380, -0.01100, 2.3270, 0.01694/
80 DATA (((B(I,J,K,3),I=1,5),J=1,4),K=1,2)/
81 > 15.8, 2.742, 0.02917, -0.0342, -0.02302,
82 > -0.9464, -0.7332, 0.04657, 0.7196, 0.9229,
83 > -0.5, 0.7148, 0.1785, 0.7338, 0.5873,
84 > -0.2118, 3.287, 0.04811, 0.08139,-0.79D-4,
85 > 6.734, 59.88, -0.3226D-2,-0.03321, 0.1059,
86 > -1.008, -2.983, 0.8432, 0.9475, 0.6954,
87 > -0.08594, 4.48, 0.3616, -0.3198, -0.6663,
88 > 0.07625, 0.9686, 0.1383D-2, 0.02132, 0.3683/
90 C...specification of sets
92 IF (Q2.LT.32.0D0) NFL=3
93 IF((Q2.GE.32.0D0).AND.(Q2.LT.200.0D0)) NFL=4
94 IF (Q2.GE.200.0D0) NFL=5
103 AT(I)=A(I,1,LF)*T**A(I,2,LF)+A(I,3,LF)*T**(-A(I,4,LF))
105 POMG=AT(1)*DX**AT(2)*(1.D0-DX)**AT(3)
112 ELSEIF(NFL.EQ.4) THEN
114 ELSEIF(NFL.EQ.5) THEN
119 BTP=B(I,1,J,LF)*T**B(I,2,J,LF)
120 BT(I,J)=BTP+B(I,3,J,LF)*T**(-B(I,4,J,LF))
124 C...singlet & non-singlet combinations
126 POM1=DX*(DX*DX+(1.D0-DX)**2)/(BT(1,J)-BT(2,J)*LOG(1.D0-DX))
127 POM2=BT(3,J)*DX**BT(4,J)*(1.D0-DX)**BT(5,J)
128 XQPOM(J)=E(J)*POM1+POM2
133 DUB=ALPEM*1.D0/6.D0*(XQPOM(2)+9.D0*XQPOM(1))
134 DDB=ALPEM*1.D0/6.D0*(XQPOM(2)-9.D0/2.D0*XQPOM(1))
138 ELSEIF (NFL.EQ.4) THEN
139 DUB=ALPEM*1.D0/8.D0*(XQPOM(2)+6.D0*XQPOM(1))
141 DDB=ALPEM*1.D0/8.D0*(XQPOM(2)-6.D0*XQPOM(1))
144 ELSEIF (NFL.EQ.5) THEN
145 DUB=ALPEM*1.D0/10.D0*(XQPOM(2)+15.D0/2.D0*XQPOM(1))
147 DDB=ALPEM*1.D0/10.D0*(XQPOM(2)-5.D0*XQPOM(1))