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0ed0a0a2 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
7 | * Permission to use, copy, modify and distribute this software and its * | |
8 | * documentation strictly for non-commercial purposes is hereby granted * | |
9 | * without fee, provided that the above copyright notice appears in all * | |
10 | * copies and that both the copyright notice and this permission notice * | |
11 | * appear in the supporting documentation. The authors make no claims * | |
12 | * about the suitability of this software for any purpose. It is * | |
13 | * provided "as is" without express or implied warranty. * | |
14 | **************************************************************************/ | |
15 | ||
16 | /* | |
17 | $Log$ | |
116cbefd | 18 | Revision 1.5 2002/10/14 14:55:35 hristov |
19 | Merging the VirtualMC branch to the main development branch (HEAD) | |
20 | ||
b9d0a01d | 21 | Revision 1.3.10.1 2002/06/10 14:57:41 hristov |
22 | Merged with v3-08-02 | |
23 | ||
24 | Revision 1.4 2002/04/17 12:48:54 morsch | |
25 | const added. | |
26 | ||
d5b6b483 | 27 | Revision 1.3 2001/03/09 13:01:41 morsch |
28 | - enum constants for paramterisation type (particle family) moved to AliGen*lib.h | |
29 | - use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants | |
30 | ||
34f60c01 | 31 | Revision 1.2 2000/11/30 07:12:50 alibrary |
32 | Introducing new Rndm and QA classes | |
33 | ||
65fb704d | 34 | Revision 1.1 2000/09/08 15:37:58 morsch |
35 | pt and y-parameterisations for PMD physics simulation. | |
36 | THIS VERSION IS JUST A TEMPLATE THE PT AND Y DISTRIBUTIONS HAVE TO BE CORRECTED !!!!. | |
37 | ||
0ed0a0a2 | 38 | */ |
39 | ||
116cbefd | 40 | #include <TMath.h> |
41 | #include <TPDGCode.h> | |
42 | ||
0ed0a0a2 | 43 | #include "AliGenPMDlib.h" |
0ed0a0a2 | 44 | |
45 | ClassImp(AliGenPMDlib) | |
46 | // | |
47 | // Neutral Pions | |
48 | ||
49 | Double_t AliGenPMDlib::PtPi0(Double_t *px, Double_t *dummy) | |
50 | { | |
51 | // | |
52 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
53 | // POWER LAW FOR PT > 500 MEV | |
54 | // MT SCALING BELOW (T=160 MEV) | |
55 | // | |
56 | const Double_t kp0 = 1.3; | |
57 | const Double_t kxn = 8.28; | |
58 | const Double_t kxlim=0.5; | |
59 | const Double_t kt=0.160; | |
60 | const Double_t kxmpi=0.139; | |
61 | const Double_t kb=1.; | |
62 | Double_t y, y1, xmpi2, ynorm, a; | |
63 | Double_t x=*px; | |
64 | // | |
65 | y1=TMath::Power(kp0/(kp0+kxlim),kxn); | |
66 | xmpi2=kxmpi*kxmpi; | |
67 | ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt)); | |
68 | a=ynorm/y1; | |
69 | if (x > kxlim) | |
70 | y=a*TMath::Power(kp0/(kp0+x),kxn); | |
71 | else | |
72 | y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt); | |
73 | return y*x; | |
74 | } | |
75 | ||
76 | // | |
77 | // y-distribution | |
78 | // | |
79 | Double_t AliGenPMDlib::YPi0( Double_t *py, Double_t *dummy) | |
80 | { | |
81 | // | |
82 | // y parametrisation for pi0 | |
83 | // | |
84 | const Double_t ka1 = 4913.; | |
85 | const Double_t ka2 = 1819.; | |
86 | const Double_t keta1 = 0.22; | |
87 | const Double_t keta2 = 3.66; | |
88 | const Double_t kdeta1 = 1.47; | |
89 | const Double_t kdeta2 = 1.51; | |
90 | Double_t y=TMath::Abs(*py); | |
91 | // | |
92 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
93 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
94 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
95 | } | |
96 | ||
97 | // particle composition | |
98 | // | |
65fb704d | 99 | Int_t AliGenPMDlib::IpPi0(TRandom *) |
0ed0a0a2 | 100 | { |
101 | // Pi0 | |
102 | return kPi0; | |
103 | } | |
104 | ||
105 | //____________________________________________________________ | |
106 | // | |
107 | // Mt-scaling | |
108 | ||
109 | Double_t AliGenPMDlib::PtScal(Double_t pt, Int_t np) | |
110 | { | |
111 | // SCALING EN MASSE PAR RAPPORT A PTPI | |
112 | // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI | |
113 | const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0}; | |
114 | // VALUE MESON/PI AT 5 GEV | |
115 | const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0}; | |
116 | np--; | |
117 | Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); | |
118 | Double_t fmax2=f5/kfmax[np]; | |
119 | // PIONS | |
120 | Double_t ptpion=100.*PtPi0(&pt, (Double_t*) 0); | |
121 | Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/ | |
122 | (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ fmax2; | |
123 | return fmtscal*ptpion; | |
124 | } | |
125 | // | |
126 | // kaon | |
127 | // | |
128 | // pt-distribution | |
129 | //____________________________________________________________ | |
130 | ||
131 | Double_t AliGenPMDlib::PtEta( Double_t *px, Double_t *dummy) | |
132 | { | |
133 | // Kaon pT | |
134 | return PtScal(*px,3); | |
135 | } | |
136 | ||
137 | // y-distribution | |
138 | //____________________________________________________________ | |
139 | Double_t AliGenPMDlib::YEta( Double_t *py, Double_t *dummy) | |
140 | { | |
141 | // | |
142 | // y parametrisation for etas | |
143 | // | |
144 | const Double_t ka1 = 4913.; | |
145 | const Double_t ka2 = 1819.; | |
146 | const Double_t keta1 = 0.22; | |
147 | const Double_t keta2 = 3.66; | |
148 | const Double_t kdeta1 = 1.47; | |
149 | const Double_t kdeta2 = 1.51; | |
150 | Double_t y=TMath::Abs(*py); | |
151 | // | |
152 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
153 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
154 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
155 | } | |
156 | ||
157 | // particle composition | |
158 | // | |
65fb704d | 159 | Int_t AliGenPMDlib::IpEta(TRandom *) |
0ed0a0a2 | 160 | { |
161 | return 221; | |
162 | } | |
163 | ||
164 | ||
165 | typedef Double_t (*GenFunc) (Double_t*, Double_t*); | |
d5b6b483 | 166 | GenFunc AliGenPMDlib::GetPt(Int_t param, const char* tname) const |
0ed0a0a2 | 167 | { |
168 | // Return pointer to pT parameterisation | |
169 | GenFunc func=NULL; | |
170 | switch (param) | |
171 | { | |
34f60c01 | 172 | case kPion: |
0ed0a0a2 | 173 | func=PtPi0; |
174 | break; | |
34f60c01 | 175 | case kEta: |
0ed0a0a2 | 176 | func=PtEta; |
177 | break; | |
178 | default: | |
179 | func=0; | |
180 | printf("<AliGenPMDlib::GetPt> unknown parametrisation\n"); | |
181 | } | |
182 | return func; | |
183 | } | |
184 | ||
d5b6b483 | 185 | GenFunc AliGenPMDlib::GetY(Int_t param, const char* tname) const |
0ed0a0a2 | 186 | { |
187 | // Return pointer to y- parameterisation | |
188 | GenFunc func=NULL; | |
189 | switch (param) | |
190 | { | |
34f60c01 | 191 | case kPion: |
0ed0a0a2 | 192 | func=YPi0; |
193 | break; | |
34f60c01 | 194 | case kEta: |
0ed0a0a2 | 195 | func=YEta; |
196 | break; | |
197 | default: | |
198 | func=0; | |
199 | printf("<AliGenPMDlib::GetY> unknown parametrisation\n"); | |
200 | } | |
201 | return func; | |
202 | ||
203 | } | |
65fb704d | 204 | typedef Int_t (*GenFuncIp) (TRandom *); |
d5b6b483 | 205 | GenFuncIp AliGenPMDlib::GetIp(Int_t param, const char* tname) const |
0ed0a0a2 | 206 | { |
207 | // Return pointer to particle type parameterisation | |
208 | GenFuncIp func=NULL; | |
209 | switch (param) | |
210 | { | |
34f60c01 | 211 | case kPion: |
0ed0a0a2 | 212 | func=IpPi0; |
213 | break; | |
34f60c01 | 214 | case kEta: |
0ed0a0a2 | 215 | func=IpEta; |
216 | break; | |
217 | default: | |
218 | printf("<AliGenPMDlib::GetIp> unknown parametrisation\n"); | |
219 | } | |
220 | return func; | |
221 | } | |
222 | ||
223 | ||
224 | ||
225 |