Requires the grid files
mrsspi10.dat ,
mrsspi15.dat ,
mrsspi20.dat ,
( mrsspi.uu
tarred, gzipped and uuencoded version of the complete package).
C***************************************************************C
C C
C PION DISTRIBUTION FUNCTIONS EXTRACTED FROM DRELL-YAN AND C
C PROMPT PHOTON PION BEAM DATA, USING (NUCLEAR TARGET C
C CORRECTED) HMRS(B) DISTRIBUTIONS FOR THE NUCLEON. C
C MAIN UNCERTAINTY IS IN SEA, HENCE FOLLOWING THREE SETS... C
C MODE=2 IS THE "BEST FIT" SET. C
C C
C MODE 1 CORRESPONDS TO A 10% MOMENTUM SEA (0.11213) C
C MODE 2 CORRESPONDS TO A 15% MOMENTUM SEA (0.16119) C
C MODE 3 CORRESPONDS TO A 20% MOMENTUM SEA (0.23785) C
C C
C (NUMBER IN BRACKETS IS LAST ENTRY IN FIRST ROW OF GRID) C
C C
C -*- C
C C
C REFERENCE: A.D. MARTIN. R.G. ROBERTS. W.J. STIRLING C
C AND P.J. SUTTON, PHYS. REV. D45 (1992) 2349. C
C -*- C
C C
C **** updated 5 November 2003 **** C
C C
C FOR THESE SETS.... C
C * LAMBDA(MSBAR,NF=4) = 190 MEV C
C * UV=DV, STR=USEA=DSEA, BTM=0 C
C C
C NOTE THAT X TIMES THE PARTON DISTRIBUTION FUNCTION C
C IS RETURNED I.E. G(X) = GLU/X ETC, AND THAT "SEA" C
C IS THE QUARK SEA / 6 I.E. UBAR(X)=DBAR(X) C
C = SEA/X FOR A PION. IF IN DOUBT, CHECK THE C
C MOMENTUM SUM RULE! NOTE ALSO THAT SCALE=Q IN GEV C
C C
C -*- C
C C
C THE RANGE OF APPLICABILITY IS CURRENTLY: C
C 10**-5 < X < 1 AND 5 < Q**2 < 1.31 * 10**6 C
C HIGHER Q**2 VALUES CAN BE SUPPLIED ON REQUEST C
C - PROBLEMS, COMMENTS ETC TO w.j.stirling@durham.ac.uk C
C C
C C
C***************************************************************C