* * $Id$ * * $Log$ * Revision 1.4 2000/09/18 10:02:36 hristov * Makefile added to PDF8 * * Revision 1.1.1.2 1996/10/30 08:30:43 cernlib * Version 7.04 * * Revision 1.1.1.1 1996/04/12 15:29:46 plothow * Version 7.01 * * #include "pdf/pilot.h" c------------------------------------------------------- subroutine SFWHI2(ZX,ZQ,ZUV,ZDV,ZUB,ZDB,ZSB,ZCB,ZGL) c------------------------------------------------------- c WHIT2 parton distribution in the photon c c INPUT: integer ic : if ic=0 then qc=0 c else qc is calculated c DOUBLE PRECISION Q2 : energy scale Q^2 (GeV^2) c DOUBLE PRECISION x : energy fraction c c OUTPUT: DOUBLE PRECISION qu : up-quark dist. c DOUBLE PRECISION qd : down- or strange-quark dist. c DOUBLE PRECISION qc : charm-quark dist. c DOUBLE PRECISION g : gluon dist. c------------------------------------------------------- c Modified by M.Tanaka on July 22, 1994. c The bug pointed out by M.Drees is fixed. c------------------------------------------------------- c Modified by I.Watanabe on July 22, 1994. c------------------------------------------------------- implicit none external WHIT2G #if defined(CERNLIB_DOUBLE) DOUBLE PRECISION #endif #if defined(CERNLIB_SINGLE) REAL #endif + ZX,ZQ,ZUV,ZDV,ZUB,ZDB,ZSB,ZCB,ZGL c arg integer ic DOUBLE PRECISION Q2,x DOUBLE PRECISION qu,qd,qc,g c const DOUBLE PRECISION q42it,q52it,lam42,lam52 DOUBLE PRECISION alinv,mc,PI c local DOUBLE PRECISION qv,qsea,cv,cs,dcv,dcs DOUBLE PRECISION A0val,A1val,A2val,Bval,Cval, $ A0sea,B0sea,BB0sea,C0sea DOUBLE PRECISION A0dcv,A1dcv,A2dcv,A3dcv,Bdcv,Cdcv DOUBLE PRECISION Adcs, B0dcs, B1dcs, Cdcs DOUBLE PRECISION x1,x2,mc2q2 DOUBLE PRECISION s,s2,s3,s4,prsccf,alstpi DOUBLE PRECISION WHIT2G c parameters parameter(lam42=0.16d0, lam52=0.091411319d0) parameter(Q42IT=4.0d0, Q52IT=100.0d0) parameter(alinv=137.036d0, mc=1.5d0) parameter(pi=3.14159265358979323846d0) common /scale/ s,s2,s3,s4,prsccf c c begin x=ZX Q2=ZQ*ZQ ic=1 c x1=1.0d0-x x2=x**2 mc2q2=mc**2/Q2 c if(Q2.lt.100.0d0) then c under 100 GeV^2 c c set scale s if(Q2.lt.4.0d0) then cccc for under 4GeV^2 prescription s= 0.0d0 prsccf = log(Q2/LAM42)/ log(Q42IT/LAM42) alstpi = 6.0d0/25.0d0/ log(Q42IT/LAM42) else s= log( log(Q2/LAM42)/ log(Q42IT/LAM42)) prsccf = 1.0d0 alstpi = 6.0d0/25.0d0/ log(Q2/LAM42) endif s2=s**2 s3=s2*s s4=s2**2 c cccccc WHIT2 quark (U100) c A0val= 1.882000d+00+s*( 1.213000d+00)+s2*( 6.970000d-01) A1val= s*(-2.361000d+00)+s2*(-1.136000d+00) A2val= s*( 5.280000d-01)+s2*( 2.406000d+00) Bval= 5.000000d-01+s*( 2.107000d-02)+s2*( 4.130000d-03) Cval= 2.500000d-01+s*(-2.376000d-01)+s2*( 2.018000d-01) $ +s3*(-5.040000d-02) A0sea= 1.237000d+00+s*( 3.390000d+00)+s2*(-1.075000d+01) $ +s3*( 1.246000d+01)+s4*(-5.580000d+00) B0sea=-7.270000d-02+s*( 1.748000d-01)+s2*(-1.392000d+00) $ +s3*( 1.711000d+00)+s4*(-7.960000d-01) BB0sea=4.290000d+00+s*( 1.787000d+01)+s2*(-5.810000d+01) $ +s3*( 8.190000d+01)+s4*(-4.140000d+01) C0sea= 1.434000d+01+s*(-4.490000d+01)+s2*( 1.197000d+02) $ +s3*(-1.585000d+02)+s4*( 7.530000d+01) c qv = prsccf/alinv/x* $ (A0val+A1val*x+A2val*x2) * x**Bval * x1**Cval qsea= prsccf/alinv/x* $ A0sea * x**(B0sea+BB0sea*x) * x1**C0sea c qu = qv/3.0d0 + qsea/6.0d0 qu = qu*x ZUV=qu ZUB=qu qd = qv/12.0d0 + qsea/6.0d0 qd = qd*x ZDV=qd ZDB=qd ZSB=qd c if((ic.ne.0) .and. (x*(1.0d0+4.0d0*mc2q2).lt.1.0d0)) then call WHIT2Q(x,mc2q2,cv,cs) qc = cv/alinv/2.0d0/PI + cs*alstpi qc = qc*x ZCB=qc else qc = 0.0d0 ZCB=qc endif c g = WHIT2G(x,Q2) g = g*x ZGL=g c else c over 100 GeV^2 c c set scale s s= log( log(Q2/LAM52)/ log(Q52IT/LAM52)) prsccf = 1.0d0 alstpi = 6.0d0/23.0d0/ log(Q2/LAM52) s2=s**2 s3=s2*s s4=s2**2 c cccccc WHIT2 quark (O100) c A0val= 3.058000d+00+s*( 2.474000d+00)+s2*( 1.002000d+00) A1val=-2.182000d+00+s*(-4.480000d+00)+s2*(-2.259000d-01) A2val= 1.522000d+00+s*( 4.300000d+00)+s2*( 1.315000d+00) Bval = 5.170000d-01+s*( 4.030000d-02)+s2*(-2.098000d-02) Cval = 1.655000d-01+s*(-2.063000d-02)+s2*( 5.370000d-02) A0sea= 1.287000d+00+s*(-2.069000d+00)+s2*( 1.157000d+01) $ +s3*(-3.570000d+01)+s4*( 3.740000d+01) B0sea=-2.340000d-01+s*(-4.430000d-01)+s2*( 1.235000d+00) $ +s3*(-3.720000d+00)+s4*( 3.840000d+00) BB0sea=6.460000d+00+s*(-1.048000d+01)+s2*( 8.980000d+01) $ +s3*(-2.847000d+02)+s4*( 2.998000d+02) C0sea= 5.350000d+00+s*( 1.011000d+01)+s2*(-1.337000d+02) $ +s3*( 4.270000d+02)+s4*(-4.570000d+02) c qv = 1.0d0/alinv/x* $ (A0val+A1val*x+A2val*x2) * x**Bval * x1**Cval qsea= 1.0d0/alinv/x* $ A0sea * x**(B0sea+BB0sea*x) * x1**C0sea c qu = qv/3.0d0 + qsea/6.0d0 qu = qu*x ZUV=qu ZUB=qu qd = qv/12.0d0 + qsea/6.0d0 qd = qd*x ZDV=qd ZDB=qd ZSB=qd g = WHIT2G(x,Q2) g = g*x ZGL=g c if((ic.ne.0) .and. (x*(1.0d0+4.0d0*mc2q2).lt.1.0d0)) then A0dcv= s*( 1.219000d-01)+s2*( 6.200000d+00) $ +s3*(-2.504000d+01)+s4*( 3.098000d+01) A1dcv= s*( 1.913000d+00)+s2*(-7.690000d+01) $ +s3*( 3.180000d+02)+s4*(-3.920000d+02) A2dcv= s*(-7.160000d+00)+s2*( 2.503000d+02) $ +s3*(-1.062000d+03)+s4*( 1.308000d+03) A3dcv= s*( 3.190000d+00)+s2*(-2.301000d+02) $ +s3*( 1.012000d+03)+s4*(-1.250000d+03) Bdcv = 4.990000d-01+s*( 3.470000d+00)+s2*(-1.526000d+01) $ +s3*( 1.967000d+01) Cdcv = 3.290000d-01+s*( 8.240000d+00)+s2*(-3.800000d+01) $ +s3*( 4.630000d+01) Adcs = s*(-2.786000d-02)+s2*( 3.490000d-02) $ +s3*(-2.223000d-02) B0dcs=-3.141000d-01+s*(-4.250000d-01)+s2*( 1.564000d-01) B1dcs= 4.720000d+00+s*(-5.480000d+00)+s2*( 2.686000d+00) Cdcs = 2.961000d+00+s*( 7.760000d-01)+s2*(-8.280000d+00) $ +s3*( 9.780000d+00) c dcv = 1.0d0/alinv/x* $ (A0dcv+x*A1dcv+x2*A2dcv+x2*x*A3dcv) * x**Bdcv * x1**Cdcv dcs = 1.0d0/alinv/x* $ Adcs * x**(B0dcs+B1dcs*x) * x1**Cdcs c call WHIT2Q(x,mc*mc/Q2,cv,cs) qc = cv/alinv/2.0d0/PI + cs*alstpi + dcs + dcv qc = qc*x ZCB=qc else qc = 0.0d0 ZCB=qc endif endif c return end