pythiaeRHIC/pythia/pygrvm.f

0001
0002 C*********************************************************************
0003
0004 C...PYGRVM
0005 C...Gives the GRV 94 M (MSbar) parton distribution function set
0006 C...in parametrized form.
0007 C...Authors: M. Glueck, E. Reya and A. Vogt.
0008
0009       SUBROUTINE PYGRVM (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  =  1.304D0 + 0.863D0 * S
0024       AKU =  0.558D0 - 0.020D0 * S
0025       BKU =          0.183D0 * S
0026       AU  = -0.113D0 + 0.283D0 * S - 0.321D0 * S2
0027       BU  =  6.843D0 - 5.089D0 * S + 2.647D0 * S2 - 0.527D0 * S3
0028       CU  =  7.771D0 - 10.09D0 * S + 2.630D0 * S2
0029       DU  =  3.315D0 + 1.145D0 * S - 0.583D0 * S2 + 0.154D0 * S3
0030       UV  = PYGRVV (X, NU, AKU, BKU, AU, BU, CU, DU)
0031
0032 C...dv :
0033       ND  =  0.102D0 - 0.017D0 * S + 0.005D0 * S2
0034       AKD =  0.270D0 - 0.019D0 * S
0035       BKD =  0.260D0
0036       AD  =  2.393D0 + 6.228D0 * S - 0.881D0 * S2
0037       BD  =  46.06D0 + 4.673D0 * S - 14.98D0 * S2 + 1.331D0 * S3
0038       CD  =  17.83D0 - 53.47D0 * S + 21.24D0 * S2
0039       DD  =  4.081D0 + 0.976D0 * S - 0.485D0 * S2 + 0.152D0 * S3
0040       DV  = PYGRVV (X, ND, AKD, BKD, AD, BD, CD, DD)
0041
0042 C...del :
0043       NE  =  0.070D0 + 0.042D0 * S - 0.011D0 * S2 + 0.004D0 * S3
0044       AKE =  0.409D0 - 0.007D0 * S
0045       BKE =  0.782D0 + 0.082D0 * S
0046       AE  = -29.65D0 + 26.49D0 * S + 5.429D0 * S2
0047       BE  =  90.20D0 - 74.97D0 * S + 4.526D0 * S2
0048       CE  =  0.0D0
0049       DE  =  8.122D0 + 2.120D0 * S - 1.088D0 * S2 + 0.231D0 * S3
0050       DEL = PYGRVV (X, NE, AKE, BKE, AE, BE, CE, DE)
0051
0052 C...udb :
0053       ALX =  0.877D0
0054       BEX =  0.561D0
0055       AKX =  0.275D0
0056       BKX =  0.0D0
0057       AGX =  0.997D0
0058       BGX =  3.210D0 - 1.866D0 * S
0059       CX  =  7.300D0
0060       DX  =  9.010D0 + 0.896D0 * DS + 0.222D0 * S2
0061       EX  =  3.077D0 + 1.446D0 * S
0062       ESX =  3.173D0 - 2.445D0 * DS + 2.207D0 * 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 =  0.756D0
0069       BES =  0.216D0
0070       AKS =  1.690D0 + 0.650D0 * DS - 0.922D0 * S
0071       AS  = -4.329D0 + 1.131D0 * S
0072       BS  =  9.568D0 - 1.744D0 * S
0073       DST =  9.377D0 + 1.088D0 * DS - 1.320D0 * S + 0.130D0 * S2
0074       EST =  3.031D0 + 1.639D0 * S
0075       ESS =  5.837D0 + 0.815D0 * S
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 =  1.014D0
0104        BEG =  1.738D0
0105        AKG =  1.724D0 + 0.157D0 * S
0106        BKG =  0.800D0 + 1.016D0 * S
0107        AG  =  7.517D0 - 2.547D0 * S
0108        BG  =  34.09D0 - 52.21D0 * DS + 17.47D0 * S
0109        CG  =  4.039D0 + 1.491D0 * S
0110        DG  =  3.404D0 + 0.830D0 * S
0111        EG  = -1.112D0 + 3.438D0 * S  - 0.302D0 * S2
0112        ESG =  3.256D0 - 0.436D0 * S
0113        GL  = PYGRVW (X, S, ALG, BEG, AKG, BKG, AG, BG, CG, DG, EG, ESG)
0114
0115        RETURN
0116        END