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 **************************************************************************/
21 #include "AliGenPMDlib.h"
23 ClassImp(AliGenPMDlib)
27 Double_t AliGenPMDlib::PtPi0(Double_t *px, Double_t */*dummy*/)
30 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
31 // POWER LAW FOR PT > 500 MEV
32 // MT SCALING BELOW (T=160 MEV)
34 const Double_t kp0 = 1.3;
35 const Double_t kxn = 8.28;
36 const Double_t kxlim=0.5;
37 const Double_t kt=0.160;
38 const Double_t kxmpi=0.139;
40 Double_t y, y1, xmpi2, ynorm, a;
43 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
45 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
48 y=a*TMath::Power(kp0/(kp0+x),kxn);
50 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
57 Double_t AliGenPMDlib::YPi0( Double_t *py, Double_t */*dummy*/)
60 // y parametrisation for pi0
62 const Double_t ka1 = 4913.;
63 const Double_t ka2 = 1819.;
64 const Double_t keta1 = 0.22;
65 const Double_t keta2 = 3.66;
66 const Double_t kdeta1 = 1.47;
67 const Double_t kdeta2 = 1.51;
68 Double_t y=TMath::Abs(*py);
70 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
71 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
72 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
75 // particle composition
77 Int_t AliGenPMDlib::IpPi0(TRandom *)
83 //____________________________________________________________
87 Double_t AliGenPMDlib::PtScal(Double_t pt, Int_t np)
89 // SCALING EN MASSE PAR RAPPORT A PTPI
90 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
91 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
92 // VALUE MESON/PI AT 5 GEV
93 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
95 Double_t f5=TMath::Power(((sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
96 Double_t fmax2=f5/kfmax[np];
98 Double_t ptpion=100.*PtPi0(&pt, (Double_t*) 0);
99 Double_t fmtscal=TMath::Power(((sqrt(pt*pt+0.018215)+2.)/
100 (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/ fmax2;
101 return fmtscal*ptpion;
107 //____________________________________________________________
109 Double_t AliGenPMDlib::PtEta( Double_t *px, Double_t */*dummy*/)
112 return PtScal(*px,3);
116 //____________________________________________________________
117 Double_t AliGenPMDlib::YEta( Double_t *py, Double_t */*dummy*/)
120 // y parametrisation for etas
122 const Double_t ka1 = 4913.;
123 const Double_t ka2 = 1819.;
124 const Double_t keta1 = 0.22;
125 const Double_t keta2 = 3.66;
126 const Double_t kdeta1 = 1.47;
127 const Double_t kdeta2 = 1.51;
128 Double_t y=TMath::Abs(*py);
130 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
131 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
132 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
135 // particle composition
137 Int_t AliGenPMDlib::IpEta(TRandom *)
143 typedef Double_t (*GenFunc) (Double_t*, Double_t*);
144 GenFunc AliGenPMDlib::GetPt(Int_t param, const char* /*tname*/) const
146 // Return pointer to pT parameterisation
158 printf("<AliGenPMDlib::GetPt> unknown parametrisation\n");
163 GenFunc AliGenPMDlib::GetY(Int_t param, const char* /*tname*/) const
165 // Return pointer to y- parameterisation
177 printf("<AliGenPMDlib::GetY> unknown parametrisation\n");
182 typedef Int_t (*GenFuncIp) (TRandom *);
183 GenFuncIp AliGenPMDlib::GetIp(Int_t param, const char* /*tname*/) const
185 // Return pointer to particle type parameterisation
196 printf("<AliGenPMDlib::GetIp> unknown parametrisation\n");