PDF/spdf/rxud.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.2  1996/10/30 08:29:18  cernlib
   6 * Version 7.04
   7 *
   8 * Revision 1.1.1.1  1996/04/12 15:29:29  plothow
   9 * Version 7.01
  10 *
  11 *
  12 #include "pdf/pilot.h"
  13       SUBROUTINE RXUD (X,QQ,XUD)
  14 C.......................................................................
  15 C.
  16 C.    F3   (GIVES VALENCE FOR U AND D)
  17 C.
  18 C.......................................................................
  19 #include "pdf/impdp.inc"
  20 #include "pdf/expdp.inc"
  21      +       BBETA
  22       DATA XLAM /0.50D00/, Q0/2.1D0/, Q00/1.8D0/
  23       DATA ONED/1.D0/, THRED/3.D0/
  24       IF(QQ.LT.Q0) QQ=Q0
  25       S=LOG(QQ/XLAM**2)/LOG(Q00/XLAM**2)
  26       S=LOG(S)
  27       ETA1=0.7D00-0.176D00*S
  28       ETA2=2.6D00+0.8D00*S
  29       XUD=THRED*(X**ETA1)*((ONED-X)**ETA2)/BBETA(ETA1,ONED+ETA2)
  30       RETURN
  31       END