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21886bb6 | 1 | * |
2 | * $Id$ | |
3 | * | |
4 | * $Log$ | |
5 | * Revision 1.1.1.2 1996/10/30 08:28:36 cernlib | |
6 | * Version 7.04 | |
7 | * | |
8 | * Revision 1.1.1.1 1996/04/12 15:29:22 plothow | |
9 | * Version 7.01 | |
10 | * | |
11 | * | |
12 | #include "pdf/pilot.h" | |
13 | * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * | |
14 | * * | |
15 | * G R V - P R O T O N - P A R A M E T R I Z A T I O N S * | |
16 | * * | |
17 | * 1994 UPDATE * | |
18 | * * | |
19 | * FOR A DETAILED EXPLANATION SEE * | |
20 | * M. GLUECK, E.REYA, A.VOGT : * | |
21 | * DO-TH 94/24 = DESY 94-206 * | |
22 | * (TO APPEAR IN Z. PHYS. C) * | |
23 | * * | |
24 | * THE PARAMETRIZATIONS ARE FITTED TO THE EVOLVED PARTONS FOR * | |
25 | * Q**2 / GEV**2 BETWEEN 0.4 AND 1.E6 * | |
26 | * X BETWEEN 1.E-5 AND 1. * | |
27 | * LARGE-X REGIONS, WHERE THE DISTRIBUTION UNDER CONSIDERATION * | |
28 | * IS NEGLIGIBLY SMALL, WERE EXCLUDED FROM THE FIT. * | |
29 | * * | |
30 | * HEAVY QUARK THRESHOLDS Q(H) = M(H) IN THE BETA FUNCTION : * | |
31 | * M(C) = 1.5, M(B) = 4.5 * | |
32 | * CORRESPONDING LAMBDA(F) VALUES IN GEV FOR Q**2 > M(H)**2 : * | |
33 | * LO : LAMBDA(3) = 0.232, LAMBDA(4) = 0.200, * | |
34 | * LAMBDA(5) = 0.153, * | |
35 | * NLO : LAMBDA(3) = 0.248, LAMBDA(4) = 0.200, * | |
36 | * LAMBDA(5) = 0.131. * | |
37 | * THE NUMBER OF ACTIVE QUARK FLAVOURS IS NF = 3 EVERYWHERE * | |
38 | * EXCEPT IN THE BETA FUNCTION, I.E. THE HEAVY QUARKS C,B,... * | |
39 | * ARE NOT PRESENT AS PARTONS IN THE Q2-EVOLUTION. * | |
40 | * IF NEEDED, HEAVY QUARK DENSITIES CAN BE TAKEN FROM THE 1991 * | |
41 | * GRV PARAMETRIZATION. * | |
42 | * * | |
43 | * NLO DISTRIBUTIONS ARE GIVEN IN MS-BAR FACTORIZATION SCHEME * | |
44 | * (SUBROUTINE GRV94HO) AS WELL AS IN THE DIS SCHEME (GRV94DI), * | |
45 | * THE LEADING ORDER PARAMETRIZATION IS PROVIDED BY "GRV94LO". * | |
46 | * * | |
47 | * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * | |
48 | * | |
49 | *...INPUT PARAMETERS : | |
50 | * | |
51 | * X = MOMENTUM FRACTION | |
52 | * Q2 = SCALE Q**2 IN GEV**2 | |
53 | * | |
54 | *...OUTPUT (ALWAYS X TIMES THE DISTRIBUTION) : | |
55 | * | |
56 | * UV = U(VAL) = U - U(BAR) | |
57 | * DV = D(VAL) = D - D(BAR) | |
58 | * DEL = D(BAR) - U(BAR) | |
59 | * UDB = U(BAR) + D(BAR) | |
60 | * SB = S = S(BAR) | |
61 | * GL = GLUON | |
62 | * | |
63 | *...LO PARAMETRIZATION : | |
64 | * | |
65 | SUBROUTINE GRV94LO (ZX,ZQ,ZUV,ZDV,ZUB,ZDB,ZSB,ZCB,ZBB,ZTB,ZGL) | |
66 | IMPLICIT REAL (A - Y) | |
67 | C+SEQ, IMPDP. | |
68 | #include "pdf/expdp.inc" | |
69 | + ZX,ZQ,ZUV,ZDV,ZDEL,ZUDB,ZUB,ZDB,ZSB,ZCB,ZBB,ZTB,ZGL | |
70 | REAL X, Q | |
71 | X = ZX | |
72 | Q = ZQ | |
73 | MU2 = 0.23 | |
74 | LAM2 = 0.2322 * 0.2322 | |
75 | Q2 = Q*Q | |
76 | ARG1 = MAX(MU2,Q2)/LAM2 | |
77 | ARG2 = MU2/LAM2 | |
78 | S = LOG ( LOG( ARG1 ) / LOG( ARG2 )) | |
79 | DS = SQRT (S) | |
80 | S2 = S * S | |
81 | S3 = S2 * S | |
82 | *...UV : | |
83 | NU = 2.284 + 0.802 * S + 0.055 * S2 | |
84 | AKU = 0.590 - 0.024 * S | |
85 | BKU = 0.131 + 0.063 * S | |
86 | AU = -0.449 - 0.138 * S - 0.076 * S2 | |
87 | BU = 0.213 + 2.669 * S - 0.728 * S2 | |
88 | CU = 8.854 - 9.135 * S + 1.979 * S2 | |
89 | DU = 2.997 + 0.753 * S - 0.076 * S2 | |
90 | UV = GR94FV (X, NU, AKU, BKU, AU, BU, CU, DU) | |
91 | ZUV = UV | |
92 | *...DV : | |
93 | ND = 0.371 + 0.083 * S + 0.039 * S2 | |
94 | AKD = 0.376 | |
95 | BKD = 0.486 + 0.062 * S | |
96 | AD = -0.509 + 3.310 * S - 1.248 * S2 | |
97 | BD = 12.41 - 10.52 * S + 2.267 * S2 | |
98 | CD = 6.373 - 6.208 * S + 1.418 * S2 | |
99 | DD = 3.691 + 0.799 * S - 0.071 * S2 | |
100 | DV = GR94FV (X, ND, AKD, BKD, AD, BD, CD, DD) | |
101 | ZDV = DV | |
102 | *...DEL : | |
103 | NE = 0.082 + 0.014 * S + 0.008 * S2 | |
104 | AKE = 0.409 - 0.005 * S | |
105 | BKE = 0.799 + 0.071 * S | |
106 | AE = -38.07 + 36.13 * S - 0.656 * S2 | |
107 | BE = 90.31 - 74.15 * S + 7.645 * S2 | |
108 | CE = 0.0 | |
109 | DE = 7.486 + 1.217 * S - 0.159 * S2 | |
110 | DEL = GR94FV (X, NE, AKE, BKE, AE, BE, CE, DE) | |
111 | ZDEL= DEL | |
112 | *...UDB : | |
113 | ALX = 1.451 | |
114 | BEX = 0.271 | |
115 | AKX = 0.410 - 0.232 * S | |
116 | BKX = 0.534 - 0.457 * S | |
117 | AGX = 0.890 - 0.140 * S | |
118 | BGX = -0.981 | |
119 | CX = 0.320 + 0.683 * S | |
120 | DX = 4.752 + 1.164 * S + 0.286 * S2 | |
121 | EX = 4.119 + 1.713 * S | |
122 | ESX = 0.682 + 2.978 * S | |
123 | UDB = GR94FW(X, S, ALX, BEX, AKX, BKX, AGX, BGX, CX, DX, EX, ESX) | |
124 | ZUDB= UDB | |
125 | *...UB | |
126 | ZUB = (ZUDB - ZDEL)/2.D0 | |
127 | *...DB | |
128 | ZDB = (ZUDB + ZDEL)/2.D0 | |
129 | *...SB : | |
130 | ALS = 0.914 | |
131 | BES = 0.577 | |
132 | AKS = 1.798 - 0.596 * S | |
133 | AS = -5.548 + 3.669 * DS - 0.616 * S | |
134 | BS = 18.92 - 16.73 * DS + 5.168 * S | |
135 | DST = 6.379 - 0.350 * S + 0.142 * S2 | |
136 | EST = 3.981 + 1.638 * S | |
137 | ESS = 6.402 | |
138 | SB = GR94FWS (X, S, ALS, BES, AKS, AS, BS, DST, EST, ESS) | |
139 | ZSB = SB | |
140 | *...GL : | |
141 | ALG = 0.524 | |
142 | BEG = 1.088 | |
143 | AKG = 1.742 - 0.930 * S | |
144 | BKG = - 0.399 * S2 | |
145 | AG = 7.486 - 2.185 * S | |
146 | BG = 16.69 - 22.74 * S + 5.779 * S2 | |
147 | CG = -25.59 + 29.71 * S - 7.296 * S2 | |
148 | DG = 2.792 + 2.215 * S + 0.422 * S2 - 0.104 * S3 | |
149 | EG = 0.807 + 2.005 * S | |
150 | ESG = 3.841 + 0.316 * S | |
151 | GL = GR94FW (X, S, ALG, BEG, AKG, BKG, AG, BG, CG, DG, EG, ESG) | |
152 | ZGL = GL | |
153 | *... | |
154 | ZCB = 0.D0 | |
155 | ZBB = 0.D0 | |
156 | ZTB = 0.D0 | |
157 | *... | |
158 | RETURN | |
159 | END |