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fe4da5cc | 1 | * |
2 | * $Id$ | |
3 | * | |
4 | * $Log$ | |
5 | * Revision 1.1.1.2 1996/10/30 08:28:06 cernlib | |
6 | * Version 7.04 | |
7 | * | |
8 | * Revision 1.2 1996/10/28 14:59:08 pdflib | |
9 | * PDFLIB new version 7.04 | |
10 | * | |
11 | * Revision 1.1.1.1 1996/04/12 15:29:17 plothow | |
12 | * Version 7.01 | |
13 | * | |
14 | * | |
15 | #include "pdf/pilot.h" | |
16 | SUBROUTINE DOPHO1(DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL) | |
17 | C******************************************************************** | |
18 | C* * | |
19 | C* Parametrization of parton distribution functions * | |
20 | C* in the photon (LO analysis) - asymptotic solution of AP eq.! * | |
21 | C* * | |
22 | C* authors: D.Duke and H.Owens (DO) * | |
23 | C* /Phys.Rev. D26 (1982) 1600/ * | |
24 | C* * | |
25 | C* Prepared by: * | |
26 | C* Krzysztof Charchula, DESY * | |
27 | C* bitnet: F1PCHA@DHHDESY3 * | |
28 | C* decnet: 13313::CHARCHULA * | |
29 | C* * | |
30 | C* Modified by: * | |
31 | C* H. Plothow-Besch/CERN-PPE * | |
32 | C* * | |
33 | C******************************************************************** | |
34 | C | |
35 | #include "pdf/impdp.inc" | |
36 | #include "pdf/expdp.inc" | |
37 | + CQ(5), | |
38 | + DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL | |
39 | PARAMETER (ALPEM=7.29927D-3, PI=3.141592D0) | |
40 | PARAMETER (ALAM=0.2D0) | |
41 | DATA CQ/0.33333D0,0.66666D0,0.33333D0,0.66666D0,0.33333D0/ | |
42 | C | |
43 | Q2 = DQ*DQ | |
44 | ALAM2=ALAM**2 | |
45 | FQ=ALPEM/(2.*PI)*LOG(Q2/ALAM2) | |
46 | C | |
47 | C...gluons | |
48 | POMG=0.194*(1.-DX)**1.03/(DX**0.97) | |
49 | DGL=POMG*FQ | |
50 | C | |
51 | C...quarks | |
52 | POM1=(1.81-1.67*DX+2.16*DX**2) | |
53 | POM2=DX**0.7/(1.-0.4*LOG(1.-DX)) | |
54 | POM3=38.D-4*(1.-DX)**1.82/(DX**1.18) | |
55 | DDB=(CQ(1)**2*POM1*POM2+POM3)*FQ | |
56 | DDV=DDB | |
57 | DUB=(CQ(2)**2*POM1*POM2+POM3)*FQ | |
58 | DUV=DUB | |
59 | DSB=(CQ(3)**2*POM1*POM2+POM3)*FQ | |
60 | DCB=(CQ(4)**2*POM1*POM2+POM3)*FQ | |
61 | DBB=(CQ(5)**2*POM1*POM2+POM3)*FQ | |
62 | RETURN | |
63 | END |