5 * Revision 1.1.1.2 1996/10/30 08:31:47 cernlib
8 * Revision 1.1.1.1 1996/04/12 15:30:05 plothow
12 #include "pdf/pilot.h"
13 C*********************************************************************
15 SUBROUTINE STROWP1(X,SCALE,UPV,DNV,SEA,STR,CHM,GL)
16 C :::::::::::::: OWENS SET 1 PION STRUCTURE FUNCTION :::::::::::::::
17 #include "pdf/impdp.inc"
18 #if defined(CERNLIB_DOUBLE)
19 DOUBLE PRECISION DGAMMA
21 #include "pdf/expdp.inc"
22 + COW(3,5,4),TS(6),XQ(9)
24 C...Expansion coefficients for up and down valence quark distributions.
25 DATA ((COW(IP,IS,1),IS=1,5),IP=1,3)/
26 1 4.0000D-01, 7.0000D-01, 0.0000D+00, 0.0000D+00, 0.0000D+00,
27 2 -6.2120D-02, 6.4780D-01, 0.0000D+00, 0.0000D+00, 0.0000D+00,
28 3 -7.1090D-03, 1.3350D-02, 0.0000D+00, 0.0000D+00, 0.0000D+00/
29 C...Expansion coefficients for gluon distribution.
30 DATA ((COW(IP,IS,2),IS=1,5),IP=1,3)/
31 1 8.8800D-01, 0.0000D+00, 3.1100D+00, 6.0000D+00, 0.0000D+00,
32 2 -1.8020D+00, -1.5760D+00, -1.3170D-01, 2.8010D+00, -1.7280D+01,
33 3 1.8120D+00, 1.2000D+00, 5.0680D-01, -1.2160D+01, 2.0490D+01/
34 C...Expansion coefficients for (up+down+strange) quark sea distribution.
35 DATA ((COW(IP,IS,3),IS=1,5),IP=1,3)/
36 1 9.0000D-01, 0.0000D+00, 5.0000D+00, 0.0000D+00, 0.0000D+00,
37 2 -2.4280D-01, -2.1200D-01, 8.6730D-01, 1.2660D+00, 2.3820D+00,
38 3 1.3860D-01, 3.6710D-03, 4.7470D-02, -2.2150D+00, 3.4820D-01/
39 C...Expansion coefficients for charm quark sea distribution.
40 DATA ((COW(IP,IS,4),IS=1,5),IP=1,3)/
41 1 0.0000D+00, -2.2120D-02, 2.8940D+00, 0.0000D+00, 0.0000D+00,
42 2 7.9280D-02, -3.7850D-01, 9.4330D+00, 5.2480D+00, 8.3880D+00,
43 3 -6.1340D-02, -1.0880D-01, -1.0852D+01, -7.1870D+00, -1.1610D+01/
45 DATA ZEROD/0.D0/, ONED/1.D0/, SIXD/6.D0/
46 DATA ALAM/0.2D0/, Q02/4.D0/, QMAX2/2.D3/
47 C...Pion structure functions from Owens.
48 C...Allowed variable range: 4 GeV^2 < Q^2 < approx 2000 GeV^2.
50 C...Determine set, Lambda and s expansion variable.
52 Q2IN = MIN( QMAX2,MAX( Q02,Q2))
53 SD = LOG( LOG( Q2IN/ALAM**2)/ LOG( Q02/ALAM**2))
55 C...Calculate structure functions.
58 230 TS(IS)=COW(1,IS,KFL)+COW(2,IS,KFL)*SD+
61 #if defined(CERNLIB_SINGLE)
62 DENOM = GAMMA(TS(1))*GAMMA(TS(2)+ONED)/GAMMA(TS(1)+TS(2)+ONED)
64 #if defined(CERNLIB_DOUBLE)
65 DENOM = DGAMMA(TS(1))*DGAMMA(TS(2)+ONED)/
66 + DGAMMA(TS(1)+TS(2)+ONED)
68 XQ(KFL)=X**TS(1)*(1.-X)**TS(2)/DENOM
70 XQ(KFL)=TS(1)*X**TS(2)*(1.-X)**TS(3)*(1.+TS(4)*X+TS(5)*X**2)
74 C...Put into output arrays.