PDF/spdf/sfgrvh.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.2  1996/10/30 08:29:48  cernlib
   6 * Version 7.04
   7 *
   8 * Revision 1.1.1.1  1996/04/12 15:29:35  plothow
   9 * Version 7.01
  10 *
  11 *
  12 #include "pdf/pilot.h"
  13 C
  14       SUBROUTINE SFGRVH(DX,DSCAL,DUPV,DDNV,DSEA,DSTR,DCHM,DBOT,DTOP,DGL)
  15 C
  16 C :::::::::::: Structure functions from Glueck, Reya and Vogt  (HO)
  17 C :::::::::::: Lambda(NF=3) = 0.200 GeV
  18 C
  19       DIMENSION XQ(7)
  20 #include "pdf/expdp.inc"
  21      +       DX,DSCAL,DUPV,DDNV,DSEA,DSTR,DCHM,DBOT,DTOP,DGL
  22       PARAMETER (ALAM=0.200)
  23 C
  24       X = DX
  25       Q2 = DSCAL**2
  26 C
  27 C     generate the individual structure fcn calls
  28 C
  29 C...Higher order parametrization of Gluck, Reya, Vogt.
  30 C...Allowed variable range: 0.2 GeV^2 < Q2 < 1E6 GeV^2; 1E-4 < x < 1.
  31
  32 C...Determine s and x.
  33           Q2IN=MIN(1.E6,MAX(0.2,Q2))
  34           SD=LOG(LOG(Q2IN/ALAM**2)/LOG(0.2/ALAM**2))
  35         SD2=SD**2
  36         XC=MAX(1.E-4,X)
  37         XL=-LOG(XC)
  38
  39 C...Calculate structure functions.
  40         XQ(1)=(1.364+0.989*SD-0.236*SD2)*XC**(0.593-0.048*SD)*
  41      &  (1.+(8.912-6.092*SD+0.852*SD2)*XC+(-16.737+7.039*SD)*XC**2+
  42      &  (10.275+0.806*SD-2.000*SD2)*XC**3)*
  43      &  (1.-XC)**(2.043+1.408*SD-0.283*SD2)
  44         XQ(2)=(0.835+0.527*SD-0.144*SD2)*XC**(0.600-0.054*SD)*
  45      &  (1.+(10.245-7.821*SD+1.325*SD2)*XC+(-19.511+10.940*SD-
  46      &  1.133*SD2)*XC**2+(12.836-2.570*SD-1.041*SD2)*XC**3)*
  47      &  (1.-XC)**(3.083+1.382*SD-0.276*SD2)
  48         XQ(3)=(XC**(0.321-0.135*SD)*((10.51-2.299*SD)+
  49      &  (-17.28+0.755*SD)*XC+(8.242+2.543*SD)*XC**2)*
  50      &  XL**(-2.023-0.103*SD)+SD**1.044*
  51      &  EXP(-(-1.178+2.792*SD)+SQRT(2.318*SD**1.673*XL)))*
  52      &  (1.-XC)**(3.720+2.337*SD-0.199*SD2)
  53         XQ(4)=SD**0.761*(1.+(6.078-2.065*SD)*XC)*(1.-XC)**(4.654+
  54      &  0.603*SD-0.326*SD2)*EXP(-(4.231+1.036*SD)+SQRT(3.419*SD**0.316*
  55      &  XL))/XL**(0.897-0.618*SD)
  56         XQ(5)=0.
  57         IF(SD.GT.0.918) XQ(5)=(SD-0.918)*(1.-XC)**(3.328+0.859*SD)*
  58      &  EXP(-(3.837+1.504*SD)+SQRT((2.150+1.291*SD)*SD**0.5*XL))
  59         XQ(6)=0.
  60         IF(SD.GT.1.353) XQ(6)=(SD-1.353)*(1.-XC)**(3.382+0.909*SD)*
  61      &  EXP(-(4.130+1.486*SD)+SQRT((2.895+1.240*SD)*SD**0.5*XL))
  62
  63 C...Put into output array - special factor for small x.
  64         CXS=1.
  65 C       IF(X.LT.1E-4.AND.ABS(XLOWPW-1.).GT.0.01)
  66 C    &  CXS=(1E-4/X)**(XLOWPW-1.)
  67       UPV = CXS*XQ(1)
  68       DUPV = UPV
  69       DNV = CXS*XQ(2)
  70       DDNV = DNV
  71       SEA = CXS*XQ(4)
  72       DSEA = SEA
  73       STR = CXS*XQ(4)
  74       DSTR = STR
  75       CHM = CXS*XQ(5)
  76       DCHM = CHM
  77       DBOT = 0.0D0
  78       DTOP = 0.0D0
  79       GL = CXS*XQ(3)
  80       DGL = GL
  81 C
  82       RETURN
  83       END