1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
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
22 Revision 1.2 2000/11/30 07:12:50 alibrary
23 Introducing new Rndm and QA classes
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 !!!!.
31 #include "AliGenPMDlib.h"
35 ClassImp(AliGenPMDlib)
39 Double_t AliGenPMDlib::PtPi0(Double_t *px, Double_t *dummy)
42 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
43 // POWER LAW FOR PT > 500 MEV
44 // MT SCALING BELOW (T=160 MEV)
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;
52 Double_t y, y1, xmpi2, ynorm, a;
55 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
57 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
60 y=a*TMath::Power(kp0/(kp0+x),kxn);
62 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
69 Double_t AliGenPMDlib::YPi0( Double_t *py, Double_t *dummy)
72 // y parametrisation for pi0
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);
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);
87 // particle composition
89 Int_t AliGenPMDlib::IpPi0(TRandom *)
95 //____________________________________________________________
99 Double_t AliGenPMDlib::PtScal(Double_t pt, Int_t np)
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};
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];
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;
119 //____________________________________________________________
121 Double_t AliGenPMDlib::PtEta( Double_t *px, Double_t *dummy)
124 return PtScal(*px,3);
128 //____________________________________________________________
129 Double_t AliGenPMDlib::YEta( Double_t *py, Double_t *dummy)
132 // y parametrisation for etas
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);
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);
147 // particle composition
149 Int_t AliGenPMDlib::IpEta(TRandom *)
155 typedef Double_t (*GenFunc) (Double_t*, Double_t*);
156 GenFunc AliGenPMDlib::GetPt(Int_t param, const char* tname) const
158 // Return pointer to pT parameterisation
170 printf("<AliGenPMDlib::GetPt> unknown parametrisation\n");
175 GenFunc AliGenPMDlib::GetY(Int_t param, const char* tname) const
177 // Return pointer to y- parameterisation
189 printf("<AliGenPMDlib::GetY> unknown parametrisation\n");
194 typedef Int_t (*GenFuncIp) (TRandom *);
195 GenFuncIp AliGenPMDlib::GetIp(Int_t param, const char* tname) const
197 // Return pointer to particle type parameterisation
208 printf("<AliGenPMDlib::GetIp> unknown parametrisation\n");