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Issue warning message if used outside allowed eta range (-8 to 8).
[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$Log$
5b0e4c0f 18Revision 1.7 2001/07/17 12:41:01 morsch
19- Calculation of fraction of event corresponding to selected pt-range corrected
20(R. Turrisi)
21- Parent weight corrected.
22
f25521b2 23Revision 1.6 2001/05/16 14:57:10 alibrary
24New files for folders and Stack
25
9e1a0ddb 26Revision 1.5 2000/12/21 16:24:06 morsch
27Coding convention clean-up
28
675e9664 29Revision 1.4 2000/11/30 07:12:50 alibrary
30Introducing new Rndm and QA classes
31
65fb704d 32Revision 1.3 2000/10/02 21:28:06 fca
33Removal of useless dependecies via forward declarations
34
94de3818 35Revision 1.2 2000/07/11 18:24:55 fca
36Coding convention corrections + few minor bug fixes
37
aee8290b 38Revision 1.1 2000/06/09 20:20:30 morsch
39Same class as previously in AliSimpleGen.cxx
40All coding rule violations except RS3 corrected (AM)
41
790bbabf 42*/
675e9664 43
44// Parameterisation of pi and K, eta and pt distributions
45// used for the ALICE TDRs.
46// eta: according to HIJING (shadowing + quenching)
47// pT : according to CDF measurement at 1.8 TeV
48// Author: andreas.morsch@cern.ch
49
50
790bbabf 51//Begin_Html
52/*
53<img src="picts/AliGeneratorClass.gif">
54</pre>
55<br clear=left>
56<font size=+2 color=red>
57<p>The responsible person for this module is
58<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
59</font>
60<pre>
61*/
62//End_Html
63// //
64///////////////////////////////////////////////////////////////////
65
66#include "AliGenHIJINGpara.h"
65fb704d 67#include "TF1.h"
790bbabf 68#include "AliRun.h"
69#include "AliConst.h"
70#include "AliPDG.h"
71
72ClassImp(AliGenHIJINGpara)
73
74AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
75{
76// copy constructor
77}
78
79//_____________________________________________________________________________
80static Double_t ptpi(Double_t *px, Double_t *)
81{
82 //
83 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
84 // POWER LAW FOR PT > 500 MEV
85 // MT SCALING BELOW (T=160 MEV)
86 //
87 const Double_t kp0 = 1.3;
88 const Double_t kxn = 8.28;
89 const Double_t kxlim=0.5;
90 const Double_t kt=0.160;
91 const Double_t kxmpi=0.139;
92 const Double_t kb=1.;
93 Double_t y, y1, xmpi2, ynorm, a;
94 Double_t x=*px;
95 //
96 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
97 xmpi2=kxmpi*kxmpi;
98 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
99 a=ynorm/y1;
100 if (x > kxlim)
101 y=a*TMath::Power(kp0/(kp0+x),kxn);
102 else
103 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
104 return y*x;
105}
106
107//_____________________________________________________________________________
108static Double_t ptscal(Double_t pt, Int_t np)
109{
110 // SCALING EN MASSE PAR RAPPORT A PTPI
111 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
112 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
113 // VALUE MESON/PI AT 5 GEV
114 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
115 np--;
116 Double_t f5=TMath::Power(((
117 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
118 Double_t fmax2=f5/kfmax[np];
119 // PIONS
120 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
121 Double_t fmtscal=TMath::Power(((
122 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
123 fmax2;
124 return fmtscal*ptpion;
125}
126
127//_____________________________________________________________________________
128static Double_t ptka( Double_t *px, Double_t *)
129{
130 //
131 // pt parametrisation for k
132 //
133 return ptscal(*px,2);
134}
135
136
137//_____________________________________________________________________________
138static Double_t etapic( Double_t *py, Double_t *)
139{
140 //
141 // eta parametrisation for pi
142 //
143 const Double_t ka1 = 4913.;
144 const Double_t ka2 = 1819.;
145 const Double_t keta1 = 0.22;
146 const Double_t keta2 = 3.66;
147 const Double_t kdeta1 = 1.47;
148 const Double_t kdeta2 = 1.51;
149 Double_t y=TMath::Abs(*py);
150 //
151 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
152 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
153 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
154}
155
156//_____________________________________________________________________________
157static Double_t etakac( Double_t *py, Double_t *)
158{
159 //
160 // eta parametrisation for ka
161 //
162 const Double_t ka1 = 497.6;
163 const Double_t ka2 = 215.6;
164 const Double_t keta1 = 0.79;
165 const Double_t keta2 = 4.09;
166 const Double_t kdeta1 = 1.54;
167 const Double_t kdeta2 = 1.40;
168 Double_t y=TMath::Abs(*py);
169 //
170 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
171 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
172 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
173}
174
175//_____________________________________________________________________________
176AliGenHIJINGpara::AliGenHIJINGpara()
177 :AliGenerator()
178{
179 //
180 // Default constructor
181 //
182 fPtpi = 0;
183 fPtka = 0;
184 fETApic = 0;
185 fETAkac = 0;
186}
187
188//_____________________________________________________________________________
189AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
190 :AliGenerator(npart)
191{
192 //
193 // Standard constructor
194 //
195 fName="HIGINGpara";
196 fTitle="HIJING Parametrisation Particle Generator";
197 fPtpi = 0;
198 fPtka = 0;
199 fETApic = 0;
200 fETAkac = 0;
201}
202
203//_____________________________________________________________________________
204AliGenHIJINGpara::~AliGenHIJINGpara()
205{
206 //
207 // Standard destructor
208 //
209 delete fPtpi;
210 delete fPtka;
211 delete fETApic;
212 delete fETAkac;
213}
214
215//_____________________________________________________________________________
216void AliGenHIJINGpara::Init()
217{
218 //
219 // Initialise the HIJING parametrisation
220 //
221 Float_t etaMin =-TMath::Log(TMath::Tan(
222 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
223 Float_t etaMax = -TMath::Log(TMath::Tan(
224 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2 225 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
226 fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf 227 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
228 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2 229
790bbabf 230 TF1 *etaPic0 = new TF1("etapic",&etapic,-7,7,0);
231 TF1 *etaKac0 = new TF1("etakac",&etakac,-7,7,0);
f25521b2 232
233 TF1 *ptPic0 = new TF1("ptpi",&ptpi,0.,15.,0);
234 TF1 *ptKac0 = new TF1("ptka",&ptka,0.,15.,0);
235
790bbabf 236 Float_t intETApi = etaPic0->Integral(-0.5, 0.5);
237 Float_t intETAka = etaKac0->Integral(-0.5, 0.5);
f25521b2 238 Float_t scalePi = 7316/(intETApi/1.5);
239 Float_t scaleKa = 684/(intETAka/2.0);
240
241// Fraction of events corresponding to the selected pt-range
242 Float_t intPt = (0.877*ptPic0->Integral(0, 15)+
243 0.123*ptKac0->Integral(0, 15));
244 Float_t intPtSel = (0.877*ptPic0->Integral(fPtMin, fPtMax)+
245 0.123*ptKac0->Integral(fPtMin, fPtMax));
246 Float_t ptFrac = intPtSel/intPt;
247
248// Fraction of events corresponding to the selected eta-range
790bbabf 249 Float_t intETASel = (scalePi*etaPic0->Integral(etaMin, etaMax)+
250 scaleKa*etaKac0->Integral(etaMin, etaMax));
f25521b2 251// Fraction of events corresponding to the selected phi-range
252 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
253
254 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
790bbabf 255
9e1a0ddb 256 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
257 ClassName(),100.*fParentWeight);
5b0e4c0f 258
259// Issue warning message if etaMin or etaMax are outside the alowed range
260// of the parametrization
261 if (etaMin < -8.001 || etaMax > 8.001) {
262 printf("\n \n WARNING FROM AliGenHIJINGPara !");
263 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
264 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
265 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
266 }
790bbabf 267}
268
269//_____________________________________________________________________________
270void AliGenHIJINGpara::Generate()
271{
272 //
273 // Generate one trigger
274 //
275
276
277 const Float_t kRaKpic=0.14;
278 const Float_t kBorne=1/(1+kRaKpic);
279 Float_t polar[3]= {0,0,0};
280 //
281 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
282 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
283 //
284 Float_t origin[3];
285 Float_t pt, pl, ptot;
286 Float_t phi, theta;
287 Float_t p[3];
288 Int_t i, part, nt, j;
289 //
290 TF1 *ptf;
291 TF1 *etaf;
292 //
293 Float_t random[6];
294 //
295 for (j=0;j<3;j++) origin[j]=fOrigin[j];
aee8290b 296 if(fVertexSmear==kPerEvent) {
65fb704d 297 Rndm(random,6);
790bbabf 298 for (j=0;j<3;j++) {
299 origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
300 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
301 }
302 }
303 for(i=0;i<fNpart;i++) {
304 while(1) {
65fb704d 305 Rndm(random,3);
790bbabf 306 if(random[0]<kBorne) {
307 part=kPions[Int_t (random[1]*3)];
308 ptf=fPtpi;
309 etaf=fETApic;
310 } else {
311 part=kKaons[Int_t (random[1]*4)];
312 ptf=fPtka;
313 etaf=fETAkac;
314 }
315 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
316 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
317 if(theta<fThetaMin || theta>fThetaMax) continue;
318 pt=ptf->GetRandom();
319 pl=pt/TMath::Tan(theta);
320 ptot=TMath::Sqrt(pt*pt+pl*pl);
321 if(ptot<fPMin || ptot>fPMax) continue;
322 p[0]=pt*TMath::Cos(phi);
323 p[1]=pt*TMath::Sin(phi);
324 p[2]=pl;
aee8290b 325 if(fVertexSmear==kPerTrack) {
65fb704d 326 Rndm(random,6);
790bbabf 327 for (j=0;j<3;j++) {
328 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
329 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
330 }
331 }
65fb704d 332 gAlice->SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
790bbabf 333 break;
334 }
335 }
336}
337
338AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
339{
340// Assignment operator
341 return *this;
342}
343
344