* * $Id$ * * $Log$ * Revision 1.1.1.2 1996/10/30 08:28:02 cernlib * Version 7.04 * * Revision 1.1.1.1 1996/04/12 15:29:15 plothow * Version 7.01 * * #include "pdf/pilot.h" SUBROUTINE DGPHO1(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... nf=3 for 1< Q2 <32 GeV2 C... nf=4 for 32< Q2 <200 GeV2 C... nf=5 for 200< Q2 <1D4 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 Q2 = DQ*DQ IF (Q2.LT.32.0D0) NFL=3 IF((Q2.GE.32.0D0).AND.(Q2.LT.200.0D0)) NFL=4 IF (Q2.GE.200.0D0) NFL=5 C C...calculations 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)=1.0D0 IF(NFL.EQ.3) THEN E(2)=9.0D0 ELSEIF(NFL.EQ.4) THEN E(2)=10.0D0 ELSEIF(NFL.EQ.5) THEN E(2)=55.0D0/6.0D0 ENDIF 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 IF (NFL.EQ.3) THEN DUB=ALPEM*1.D0/6.D0*(XQPOM(2)+9.D0*XQPOM(1)) DDB=ALPEM*1.D0/6.D0*(XQPOM(2)-9.D0/2.D0*XQPOM(1)) DSB=DDB DCB=0.D0 DBB=0.D0 ELSEIF (NFL.EQ.4) THEN DUB=ALPEM*1.D0/8.D0*(XQPOM(2)+6.D0*XQPOM(1)) DCB=DUB DDB=ALPEM*1.D0/8.D0*(XQPOM(2)-6.D0*XQPOM(1)) DSB=DDB DBB=0.D0 ELSEIF (NFL.EQ.5) THEN DUB=ALPEM*1.D0/10.D0*(XQPOM(2)+15.D0/2.D0*XQPOM(1)) DCB=DUB DDB=ALPEM*1.D0/10.D0*(XQPOM(2)-5.D0*XQPOM(1)) DSB=DDB DBB=DDB ENDIF DUV=DUB DDV=DDB C RETURN END