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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 | $Log$ | |
d5b6b483 | 18 | Revision 1.3 2001/03/09 13:01:41 morsch |
19 | - enum constants for paramterisation type (particle family) moved to AliGen*lib.h | |
20 | - use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants | |
21 | ||
34f60c01 | 22 | Revision 1.2 2000/11/30 07:12:50 alibrary |
23 | Introducing new Rndm and QA classes | |
24 | ||
65fb704d | 25 | Revision 1.1 2000/09/08 15:37:58 morsch |
26 | pt and y-parameterisations for PMD physics simulation. | |
27 | THIS VERSION IS JUST A TEMPLATE THE PT AND Y DISTRIBUTIONS HAVE TO BE CORRECTED !!!!. | |
28 | ||
0ed0a0a2 | 29 | */ |
30 | ||
31 | #include "AliGenPMDlib.h" | |
0ed0a0a2 | 32 | #include "AliPDG.h" |
65fb704d | 33 | #include "TMath.h" |
0ed0a0a2 | 34 | |
35 | ClassImp(AliGenPMDlib) | |
36 | // | |
37 | // Neutral Pions | |
38 | ||
39 | Double_t AliGenPMDlib::PtPi0(Double_t *px, Double_t *dummy) | |
40 | { | |
41 | // | |
42 | // PT-PARAMETERIZATION CDF, PRL 61(88) 1819 | |
43 | // POWER LAW FOR PT > 500 MEV | |
44 | // MT SCALING BELOW (T=160 MEV) | |
45 | // | |
46 | const Double_t kp0 = 1.3; | |
47 | const Double_t kxn = 8.28; | |
48 | const Double_t kxlim=0.5; | |
49 | const Double_t kt=0.160; | |
50 | const Double_t kxmpi=0.139; | |
51 | const Double_t kb=1.; | |
52 | Double_t y, y1, xmpi2, ynorm, a; | |
53 | Double_t x=*px; | |
54 | // | |
55 | y1=TMath::Power(kp0/(kp0+kxlim),kxn); | |
56 | xmpi2=kxmpi*kxmpi; | |
57 | ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt)); | |
58 | a=ynorm/y1; | |
59 | if (x > kxlim) | |
60 | y=a*TMath::Power(kp0/(kp0+x),kxn); | |
61 | else | |
62 | y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt); | |
63 | return y*x; | |
64 | } | |
65 | ||
66 | // | |
67 | // y-distribution | |
68 | // | |
69 | Double_t AliGenPMDlib::YPi0( Double_t *py, Double_t *dummy) | |
70 | { | |
71 | // | |
72 | // y parametrisation for pi0 | |
73 | // | |
74 | const Double_t ka1 = 4913.; | |
75 | const Double_t ka2 = 1819.; | |
76 | const Double_t keta1 = 0.22; | |
77 | const Double_t keta2 = 3.66; | |
78 | const Double_t kdeta1 = 1.47; | |
79 | const Double_t kdeta2 = 1.51; | |
80 | Double_t y=TMath::Abs(*py); | |
81 | // | |
82 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
83 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
84 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
85 | } | |
86 | ||
87 | // particle composition | |
88 | // | |
65fb704d | 89 | Int_t AliGenPMDlib::IpPi0(TRandom *) |
0ed0a0a2 | 90 | { |
91 | // Pi0 | |
92 | return kPi0; | |
93 | } | |
94 | ||
95 | //____________________________________________________________ | |
96 | // | |
97 | // Mt-scaling | |
98 | ||
99 | Double_t AliGenPMDlib::PtScal(Double_t pt, Int_t np) | |
100 | { | |
101 | // SCALING EN MASSE PAR RAPPORT A PTPI | |
102 | // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI | |
103 | const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0}; | |
104 | // VALUE MESON/PI AT 5 GEV | |
105 | const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0}; | |
106 | np--; | |
107 | Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3); | |
108 | Double_t fmax2=f5/kfmax[np]; | |
109 | // PIONS | |
110 | Double_t ptpion=100.*PtPi0(&pt, (Double_t*) 0); | |
111 | Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/ | |
112 | (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ fmax2; | |
113 | return fmtscal*ptpion; | |
114 | } | |
115 | // | |
116 | // kaon | |
117 | // | |
118 | // pt-distribution | |
119 | //____________________________________________________________ | |
120 | ||
121 | Double_t AliGenPMDlib::PtEta( Double_t *px, Double_t *dummy) | |
122 | { | |
123 | // Kaon pT | |
124 | return PtScal(*px,3); | |
125 | } | |
126 | ||
127 | // y-distribution | |
128 | //____________________________________________________________ | |
129 | Double_t AliGenPMDlib::YEta( Double_t *py, Double_t *dummy) | |
130 | { | |
131 | // | |
132 | // y parametrisation for etas | |
133 | // | |
134 | const Double_t ka1 = 4913.; | |
135 | const Double_t ka2 = 1819.; | |
136 | const Double_t keta1 = 0.22; | |
137 | const Double_t keta2 = 3.66; | |
138 | const Double_t kdeta1 = 1.47; | |
139 | const Double_t kdeta2 = 1.51; | |
140 | Double_t y=TMath::Abs(*py); | |
141 | // | |
142 | Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1); | |
143 | Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2); | |
144 | return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2); | |
145 | } | |
146 | ||
147 | // particle composition | |
148 | // | |
65fb704d | 149 | Int_t AliGenPMDlib::IpEta(TRandom *) |
0ed0a0a2 | 150 | { |
151 | return 221; | |
152 | } | |
153 | ||
154 | ||
155 | typedef Double_t (*GenFunc) (Double_t*, Double_t*); | |
d5b6b483 | 156 | GenFunc AliGenPMDlib::GetPt(Int_t param, const char* tname) const |
0ed0a0a2 | 157 | { |
158 | // Return pointer to pT parameterisation | |
159 | GenFunc func=NULL; | |
160 | switch (param) | |
161 | { | |
34f60c01 | 162 | case kPion: |
0ed0a0a2 | 163 | func=PtPi0; |
164 | break; | |
34f60c01 | 165 | case kEta: |
0ed0a0a2 | 166 | func=PtEta; |
167 | break; | |
168 | default: | |
169 | func=0; | |
170 | printf("<AliGenPMDlib::GetPt> unknown parametrisation\n"); | |
171 | } | |
172 | return func; | |
173 | } | |
174 | ||
d5b6b483 | 175 | GenFunc AliGenPMDlib::GetY(Int_t param, const char* tname) const |
0ed0a0a2 | 176 | { |
177 | // Return pointer to y- parameterisation | |
178 | GenFunc func=NULL; | |
179 | switch (param) | |
180 | { | |
34f60c01 | 181 | case kPion: |
0ed0a0a2 | 182 | func=YPi0; |
183 | break; | |
34f60c01 | 184 | case kEta: |
0ed0a0a2 | 185 | func=YEta; |
186 | break; | |
187 | default: | |
188 | func=0; | |
189 | printf("<AliGenPMDlib::GetY> unknown parametrisation\n"); | |
190 | } | |
191 | return func; | |
192 | ||
193 | } | |
65fb704d | 194 | typedef Int_t (*GenFuncIp) (TRandom *); |
d5b6b483 | 195 | GenFuncIp AliGenPMDlib::GetIp(Int_t param, const char* tname) const |
0ed0a0a2 | 196 | { |
197 | // Return pointer to particle type parameterisation | |
198 | GenFuncIp func=NULL; | |
199 | switch (param) | |
200 | { | |
34f60c01 | 201 | case kPion: |
0ed0a0a2 | 202 | func=IpPi0; |
203 | break; | |
34f60c01 | 204 | case kEta: |
0ed0a0a2 | 205 | func=IpEta; |
206 | break; | |
207 | default: | |
208 | printf("<AliGenPMDlib::GetIp> unknown parametrisation\n"); | |
209 | } | |
210 | return func; | |
211 | } | |
212 | ||
213 | ||
214 | ||
215 |