--- /dev/null
+*
+* $Id$
+*
+* $Log$
+* Revision 1.1.1.2 1996/10/30 08:28:04 cernlib
+* Version 7.04
+*
+* Revision 1.1.1.1 1996/04/12 15:29:15 plothow
+* Version 7.01
+*
+*
+#include "pdf/pilot.h"
+ SUBROUTINE DGPHO2(DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL)
+C********************************************************************
+C* *
+C* Parametrization of parton distribution functions *
+C* in the photon (LO analysis) - full solution of AP eq.! *
+C* *
+C* authors: M.Drees and K.Grassie (DG) *
+C* /Z. Phys. C28 (1985) 451/ *
+C* *
+C* Prepared by: *
+C* Krzysztof Charchula, DESY *
+C* bitnet: F1PCHA@DHHDESY3 *
+C* decnet: 13313::CHARCHULA *
+C* *
+C* Modified by: *
+C* H. Plothow-Besch/CERN-PPE *
+C* *
+C********************************************************************
+C
+#include "pdf/impdp.inc"
+#include "pdf/expdp.inc"
+ + A(3,4,3),AT(3),
+ + B(5,4,2,3),BT(5,2),XQPOM(2),E(2),
+ + DX,DQ,DUV,DDV,DUB,DDB,DSB,DCB,DBB,DGL
+ PARAMETER (ALPEM=7.29927D-3, PI=3.141592D0)
+ PARAMETER (ALAM=0.4D0)
+C...comments
+C...--------------------------------------------------
+C... with nf=3 (valid for 1< Q2 <50 GeV2)
+C...--------------------------------------------------
+C
+C...initialization of gluon parameters array for DG
+ DATA (((A(I,J,K),I=1,3),J=1,4),K=1,3)/
+ > -0.20700, -0.19870, 5.1190,
+ > 0.61580, 0.62570, -0.2752,
+ > 1.07400, 8.35200, -6.9930,
+ > 0.00000, 5.02400, 2.2980,
+ > 0.8926D-2,0.0509, -0.2313,
+ > 0.65940, 0.27740, 0.1382,
+ > 0.47660, -0.39060, 6.5420,
+ > 0.01975, -0.32120, 0.5162,
+ > 0.03197, -0.618D-2,-0.1216,
+ > 1.01800, 0.94760, 0.9047,
+ > 0.24610, -0.60940, 2.6530,
+ > 0.02707, -0.01067, 0.2003D-2/
+C
+C...initialization of quark parameters array for DG
+ DATA (((B(I,J,K,1),I=1,5),J=1,4),K=1,2)/
+ > 2.2850, 6.0730, -0.4202, -0.0808, 0.0553,
+ > -0.0153, -0.8132, 0.0178, 0.6346, 1.1360,
+ > 1.33D3, -41.310, 0.9216, 1.2080, 0.9512,
+ > 4.2190, 3.1650, 0.1800, 0.2030, 0.0116,
+ > 16.690, 0.1760, -0.0208, -0.0168, -0.1986,
+ > -0.7916, 0.0479, 0.3386D-2, 1.3530, 1.1000,
+ > 1.0990D3, 1.0470, 4.8530, 1.4260, 1.1360,
+ > 4.4280, 0.0250, 0.8404, 1.2390, -0.2779/
+ DATA (((B(I,J,K,2),I=1,5),J=1,4),K=1,2)/
+ > -0.3711, -0.1717, 0.08766, -0.8915, -0.1816,
+ > 1.0610, 0.7815, 0.02197, 0.2857, 0.5866,
+ > 4.7580, 1.5350, 0.10960, 2.9730, 2.4210,
+ > -0.0150, 0.7067D-2,0.20400, 0.1185, 0.4059,
+ > -0.1207, 25.000, -0.01230, -0.0919, 0.02015,
+ > 1.0710, -1.6480, 1.16200, 0.7912, 0.9869,
+ > 1.9770, -0.01563, 0.48240, 0.6397, -0.07036,
+ > -0.8625D-2,6.4380, -0.01100, 2.3270, 0.01694/
+ DATA (((B(I,J,K,3),I=1,5),J=1,4),K=1,2)/
+ > 15.8, 2.742, 0.02917, -0.0342, -0.02302,
+ > -0.9464, -0.7332, 0.04657, 0.7196, 0.9229,
+ > -0.5, 0.7148, 0.1785, 0.7338, 0.5873,
+ > -0.2118, 3.287, 0.04811, 0.08139,-0.79D-4,
+ > 6.734, 59.88, -0.3226D-2,-0.03321, 0.1059,
+ > -1.008, -2.983, 0.8432, 0.9475, 0.6954,
+ > -0.08594, 4.48, 0.3616, -0.3198, -0.6663,
+ > 0.07625, 0.9686, 0.1383D-2, 0.02132, 0.3683/
+C
+C...specification of sets
+ NFL=3
+C
+C...calculations
+ Q2 = DQ*DQ
+ ALAM2=ALAM**2
+ T=LOG(Q2/ALAM2)
+ LF=NFL-2
+C
+C...gluons
+ DO 11 I=1,3
+ AT(I)=A(I,1,LF)*T**A(I,2,LF)+A(I,3,LF)*T**(-A(I,4,LF))
+ 11 CONTINUE
+ POMG=AT(1)*DX**AT(2)*(1.D0-DX)**AT(3)
+ DGL=POMG*ALPEM
+C
+C...quarks
+ E(1)=1.D0
+ E(2)=9.D0
+ DO 13 J=1,2
+ DO 15 I=1,5
+ BTP=B(I,1,J,LF)*T**B(I,2,J,LF)
+ BT(I,J)=BTP+B(I,3,J,LF)*T**(-B(I,4,J,LF))
+ 15 CONTINUE
+ 13 CONTINUE
+C
+C...singlet & non-singlet combinations
+ DO 17 J=1,2
+ POM1=DX*(DX*DX+(1.D0-DX)**2)/(BT(1,J)-BT(2,J)*LOG(1.D0-DX))
+ POM2=BT(3,J)*DX**BT(4,J)*(1.D0-DX)**BT(5,J)
+ XQPOM(J)=E(J)*POM1+POM2
+ 17 CONTINUE
+C
+C...quarks flavours
+ DUB=ALPEM*1.D0/6.D0*(XQPOM(2)+9.D0*XQPOM(1))
+ DUV=DUB
+ DDB=ALPEM*1.D0/6.D0*(XQPOM(2)-9.D0/2.D0*XQPOM(1))
+ DDV=DDB
+ DSB=DDB
+ DCB=0.D0
+ DBB=0.D0
+C
+ RETURN
+ END
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff