Update of SSD simulation and reconstruction code by Boris and Enrico.
[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGpara.cxx
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790bbabf 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$Log$
675e9664 18Revision 1.4 2000/11/30 07:12:50 alibrary
19Introducing new Rndm and QA classes
20
65fb704d 21Revision 1.3 2000/10/02 21:28:06 fca
22Removal of useless dependecies via forward declarations
23
94de3818 24Revision 1.2 2000/07/11 18:24:55 fca
25Coding convention corrections + few minor bug fixes
26
aee8290b 27Revision 1.1 2000/06/09 20:20:30 morsch
28Same class as previously in AliSimpleGen.cxx
29All coding rule violations except RS3 corrected (AM)
30
790bbabf 31*/
675e9664 32
33// Parameterisation of pi and K, eta and pt distributions
34// used for the ALICE TDRs.
35// eta: according to HIJING (shadowing + quenching)
36// pT : according to CDF measurement at 1.8 TeV
37// Author: andreas.morsch@cern.ch
38
39
790bbabf 40//Begin_Html
41/*
42<img src="picts/AliGeneratorClass.gif">
43</pre>
44<br clear=left>
45<font size=+2 color=red>
46<p>The responsible person for this module is
47<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
48</font>
49<pre>
50*/
51//End_Html
52// //
53///////////////////////////////////////////////////////////////////
54
55#include "AliGenHIJINGpara.h"
65fb704d 56#include "TF1.h"
790bbabf 57#include "AliRun.h"
58#include "AliConst.h"
59#include "AliPDG.h"
60
61ClassImp(AliGenHIJINGpara)
62
63AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
64{
65// copy constructor
66}
67
68//_____________________________________________________________________________
69static Double_t ptpi(Double_t *px, Double_t *)
70{
71 //
72 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
73 // POWER LAW FOR PT > 500 MEV
74 // MT SCALING BELOW (T=160 MEV)
75 //
76 const Double_t kp0 = 1.3;
77 const Double_t kxn = 8.28;
78 const Double_t kxlim=0.5;
79 const Double_t kt=0.160;
80 const Double_t kxmpi=0.139;
81 const Double_t kb=1.;
82 Double_t y, y1, xmpi2, ynorm, a;
83 Double_t x=*px;
84 //
85 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
86 xmpi2=kxmpi*kxmpi;
87 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
88 a=ynorm/y1;
89 if (x > kxlim)
90 y=a*TMath::Power(kp0/(kp0+x),kxn);
91 else
92 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
93 return y*x;
94}
95
96//_____________________________________________________________________________
97static Double_t ptscal(Double_t pt, Int_t np)
98{
99 // SCALING EN MASSE PAR RAPPORT A PTPI
100 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
101 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
102 // VALUE MESON/PI AT 5 GEV
103 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
104 np--;
105 Double_t f5=TMath::Power(((
106 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
107 Double_t fmax2=f5/kfmax[np];
108 // PIONS
109 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
110 Double_t fmtscal=TMath::Power(((
111 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
112 fmax2;
113 return fmtscal*ptpion;
114}
115
116//_____________________________________________________________________________
117static Double_t ptka( Double_t *px, Double_t *)
118{
119 //
120 // pt parametrisation for k
121 //
122 return ptscal(*px,2);
123}
124
125
126//_____________________________________________________________________________
127static Double_t etapic( Double_t *py, Double_t *)
128{
129 //
130 // eta parametrisation for pi
131 //
132 const Double_t ka1 = 4913.;
133 const Double_t ka2 = 1819.;
134 const Double_t keta1 = 0.22;
135 const Double_t keta2 = 3.66;
136 const Double_t kdeta1 = 1.47;
137 const Double_t kdeta2 = 1.51;
138 Double_t y=TMath::Abs(*py);
139 //
140 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
141 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
142 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
143}
144
145//_____________________________________________________________________________
146static Double_t etakac( Double_t *py, Double_t *)
147{
148 //
149 // eta parametrisation for ka
150 //
151 const Double_t ka1 = 497.6;
152 const Double_t ka2 = 215.6;
153 const Double_t keta1 = 0.79;
154 const Double_t keta2 = 4.09;
155 const Double_t kdeta1 = 1.54;
156 const Double_t kdeta2 = 1.40;
157 Double_t y=TMath::Abs(*py);
158 //
159 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
160 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
161 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
162}
163
164//_____________________________________________________________________________
165AliGenHIJINGpara::AliGenHIJINGpara()
166 :AliGenerator()
167{
168 //
169 // Default constructor
170 //
171 fPtpi = 0;
172 fPtka = 0;
173 fETApic = 0;
174 fETAkac = 0;
175}
176
177//_____________________________________________________________________________
178AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
179 :AliGenerator(npart)
180{
181 //
182 // Standard constructor
183 //
184 fName="HIGINGpara";
185 fTitle="HIJING Parametrisation Particle Generator";
186 fPtpi = 0;
187 fPtka = 0;
188 fETApic = 0;
189 fETAkac = 0;
190}
191
192//_____________________________________________________________________________
193AliGenHIJINGpara::~AliGenHIJINGpara()
194{
195 //
196 // Standard destructor
197 //
198 delete fPtpi;
199 delete fPtka;
200 delete fETApic;
201 delete fETAkac;
202}
203
204//_____________________________________________________________________________
205void AliGenHIJINGpara::Init()
206{
207 //
208 // Initialise the HIJING parametrisation
209 //
210 Float_t etaMin =-TMath::Log(TMath::Tan(
211 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
212 Float_t etaMax = -TMath::Log(TMath::Tan(
213 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
214 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
215 fPtka = new TF1("ptka",&ptka,0,20,0);
216 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
217 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
218 TF1 *etaPic0 = new TF1("etapic",&etapic,-7,7,0);
219 TF1 *etaKac0 = new TF1("etakac",&etakac,-7,7,0);
220 Float_t intETApi = etaPic0->Integral(-0.5, 0.5);
221 Float_t intETAka = etaKac0->Integral(-0.5, 0.5);
222 Float_t scalePi=7316/(intETApi/1.5);
223 Float_t scaleKa= 684/(intETAka/2.0);
224
225 Float_t intPt = (0.877*etaPic0->Integral(0, 15)+
226 0.123*etaKac0->Integral(0, 15));
227 Float_t intPtSel = (0.877*etaPic0->Integral(fPtMin, fPtMax)+
228 0.123*etaKac0->Integral(fPtMin, fPtMax));
229 Float_t ptFrac = intPtSel/intPt;
230
231
232 Float_t intETASel = (scalePi*etaPic0->Integral(etaMin, etaMax)+
233 scaleKa*etaKac0->Integral(etaMin, etaMax));
234 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
235 fParentWeight = Float_t(fNpart)/intETASel*ptFrac*phiFrac;
236
237 printf("\n The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ", 100.*fParentWeight);
238
239}
240
241//_____________________________________________________________________________
242void AliGenHIJINGpara::Generate()
243{
244 //
245 // Generate one trigger
246 //
247
248
249 const Float_t kRaKpic=0.14;
250 const Float_t kBorne=1/(1+kRaKpic);
251 Float_t polar[3]= {0,0,0};
252 //
253 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
254 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
255 //
256 Float_t origin[3];
257 Float_t pt, pl, ptot;
258 Float_t phi, theta;
259 Float_t p[3];
260 Int_t i, part, nt, j;
261 //
262 TF1 *ptf;
263 TF1 *etaf;
264 //
265 Float_t random[6];
266 //
267 for (j=0;j<3;j++) origin[j]=fOrigin[j];
aee8290b 268 if(fVertexSmear==kPerEvent) {
65fb704d 269 Rndm(random,6);
790bbabf 270 for (j=0;j<3;j++) {
271 origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
272 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
273 }
274 }
275 for(i=0;i<fNpart;i++) {
276 while(1) {
65fb704d 277 Rndm(random,3);
790bbabf 278 if(random[0]<kBorne) {
279 part=kPions[Int_t (random[1]*3)];
280 ptf=fPtpi;
281 etaf=fETApic;
282 } else {
283 part=kKaons[Int_t (random[1]*4)];
284 ptf=fPtka;
285 etaf=fETAkac;
286 }
287 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
288 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
289 if(theta<fThetaMin || theta>fThetaMax) continue;
290 pt=ptf->GetRandom();
291 pl=pt/TMath::Tan(theta);
292 ptot=TMath::Sqrt(pt*pt+pl*pl);
293 if(ptot<fPMin || ptot>fPMax) continue;
294 p[0]=pt*TMath::Cos(phi);
295 p[1]=pt*TMath::Sin(phi);
296 p[2]=pl;
aee8290b 297 if(fVertexSmear==kPerTrack) {
65fb704d 298 Rndm(random,6);
790bbabf 299 for (j=0;j<3;j++) {
300 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
301 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
302 }
303 }
65fb704d 304 gAlice->SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
790bbabf 305 break;
306 }
307 }
308}
309
310AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
311{
312// Assignment operator
313 return *this;
314}
315
316