pythiaeRHIC/pythia/pygrvd.f

0001
0002 C*********************************************************************
0003
0004 C...PYGRVD
0005 C...Gives the GRV 94 D (DIS) parton distribution function set
0006 C...in parametrized form.
0007 C...Authors: M. Glueck, E. Reya and A. Vogt.
0008
0009       SUBROUTINE PYGRVD (X, Q2, UV, DV, DEL, UDB, SB, CHM, BOT, GL)
0010
0011 C...Double precision declaration.
0012       IMPLICIT DOUBLE PRECISION (A - Z)
0013
0014 C...Common expressions.
0015       MU2  = 0.34D0
0016       LAM2 = 0.248D0 * 0.248D0
0017       S  = LOG (LOG(Q2/LAM2) / LOG(MU2/LAM2))
0018       DS = SQRT (S)
0019       S2 = S * S
0020       S3 = S2 * S
0021
0022 C...uv :
0023       NU  =  2.484D0 + 0.116D0 * S + 0.093D0 * S2
0024       AKU =  0.563D0 - 0.025D0 * S
0025       BKU =  0.054D0 + 0.154D0 * S
0026       AU  = -0.326D0 - 0.058D0 * S - 0.135D0 * S2
0027       BU  = -3.322D0 + 8.259D0 * S - 3.119D0 * S2 + 0.291D0 * S3
0028       CU  =  11.52D0 - 12.99D0 * S + 3.161D0 * S2
0029       DU  =  2.808D0 + 1.400D0 * S - 0.557D0 * S2 + 0.119D0 * S3
0030       UV  = PYGRVV (X, NU, AKU, BKU, AU, BU, CU, DU)
0031
0032 C...dv :
0033       ND  =  0.156D0 - 0.017D0 * S
0034       AKD =  0.299D0 - 0.022D0 * S
0035       BKD =  0.259D0 - 0.015D0 * S
0036       AD  =  3.445D0 + 1.278D0 * S + 0.326D0 * S2
0037       BD  = -6.934D0 + 37.45D0 * S - 18.95D0 * S2 + 1.463D0 * S3
0038       CD  =  55.45D0 - 69.92D0 * S + 20.78D0 * S2
0039       DD  =  3.577D0 + 1.441D0 * S - 0.683D0 * S2 + 0.179D0 * S3
0040       DV  = PYGRVV (X, ND, AKD, BKD, AD, BD, CD, DD)
0041
0042 C...del :
0043       NE  =  0.099D0 + 0.019D0 * S + 0.002D0 * S2
0044       AKE =  0.419D0 - 0.013D0 * S
0045       BKE =  1.064D0 - 0.038D0 * S
0046       AE  = -44.00D0 + 98.70D0 * S - 14.79D0 * S2
0047       BE  =  28.59D0 - 40.94D0 * S - 13.66D0 * S2 + 2.523D0 * S3
0048       CE  =  84.57D0 - 108.8D0 * S + 31.52D0 * S2
0049       DE  =  7.469D0 + 2.480D0 * S - 0.866D0 * S2
0050       DEL = PYGRVV (X, NE, AKE, BKE, AE, BE, CE, DE)
0051
0052 C...udb :
0053       ALX =  1.215D0
0054       BEX =  0.466D0
0055       AKX =  0.326D0 + 0.150D0 * S
0056       BKX =  0.956D0 + 0.405D0 * S
0057       AGX =  0.272D0
0058       BGX =  3.794D0 - 2.359D0 * DS
0059       CX  =  2.014D0
0060       DX  =  7.941D0 + 0.534D0 * DS - 0.940D0 * S + 0.410D0 * S2
0061       EX  =  3.049D0 + 1.597D0 * S
0062       ESX =  4.396D0 - 4.594D0 * DS + 3.268D0 * S
0063       UDB = PYGRVW (X, S, ALX, BEX, AKX, BKX, AGX, BGX, CX,
0064      & DX, EX, ESX)
0065
0066 C...sb :
0067       STS =  0D0
0068       ALS =  0.175D0
0069       BES =  0.344D0
0070       AKS =  1.415D0 - 0.641D0 * DS
0071       AS  =  0.580D0 - 9.763D0 * DS + 6.795D0 * S  - 0.558D0 * S2
0072       BS  =  5.617D0 + 5.709D0 * DS - 3.972D0 * S
0073       DST =  13.78D0 - 9.581D0 * S  + 5.370D0 * S2 - 0.996D0 * S3
0074       EST =  4.546D0 + 0.372D0 * S2
0075       ESS =  5.053D0 - 1.070D0 * S  + 0.805D0 * S2
0076       SB  = PYGRVS (X, S, STS, ALS, BES, AKS, AS, BS, DST, EST, ESS)
0077
0078 C...cb :
0079       STC =  0.820D0
0080       ALC =  0.98D0
0081       BEC =  0D0
0082       AKC = -0.625D0 - 0.523D0 * S
0083       AC  =  0D0
0084       BC  =  1.896D0 + 1.616D0 * S
0085       DCT =  4.12D0  + 0.683D0 * S
0086       ECT =  4.36D0  + 1.328D0 * S
0087       ESC =  0.677D0 + 0.679D0 * S
0088       CHM = PYGRVS (X, S, STC, ALC, BEC, AKC, AC, BC, DCT, ECT, ESC)
0089
0090 C...bb :
0091       STB =  1.297D0
0092       ALB =  0.99D0
0093       BEB =  0D0
0094       AKB =          - 0.193D0 * S
0095       AB  =  0D0
0096       BB  =  0D0
0097       DBT =  3.447D0 + 0.927D0 * S
0098       EBT =  4.68D0  + 1.259D0 * S
0099       ESB =  1.892D0 + 2.199D0 * S
0100       BOT = PYGRVS (X, S, STB, ALB, BEB, AKB, AB, BB, DBT, EBT, ESB)
0101
0102 C...gl :
0103       ALG =  1.258D0
0104       BEG =  1.846D0
0105       AKG =  2.423D0
0106       BKG =  2.427D0 + 1.311D0 * S  - 0.153D0 * S2
0107       AG  =  25.09D0 - 7.935D0 * S
0108       BG  = -14.84D0 - 124.3D0 * DS + 72.18D0 * S
0109       CG  =  590.3D0 - 173.8D0 * S
0110       DG  =  5.196D0 + 1.857D0 * S
0111       EG  = -1.648D0 + 3.988D0 * S  - 0.432D0 * S2
0112       ESG =  3.232D0 - 0.542D0 * S
0113       GL  = PYGRVW (X, S, ALG, BEG, AKG, BKG, AG, BG, CG, DG, EG, ESG)
0114
0115       RETURN
0116       END