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