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[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$Log$
6b236b6f 18Revision 1.10 2001/10/15 16:44:46 morsch
19- Possibility for vertex distribution truncation.
20- Write mc header with vertex position.
21
971816d4 22Revision 1.9 2001/07/27 17:09:36 morsch
23Use local SetTrack, KeepTrack and SetHighWaterMark methods
24to delegate either to local stack or to stack owned by AliRun.
25(Piotr Skowronski, A.M.)
26
a99cf51f 27Revision 1.8 2001/07/20 11:03:58 morsch
28Issue warning message if used outside allowed eta range (-8 to 8).
29
5b0e4c0f 30Revision 1.7 2001/07/17 12:41:01 morsch
31- Calculation of fraction of event corresponding to selected pt-range corrected
32(R. Turrisi)
33- Parent weight corrected.
34
f25521b2 35Revision 1.6 2001/05/16 14:57:10 alibrary
36New files for folders and Stack
37
9e1a0ddb 38Revision 1.5 2000/12/21 16:24:06 morsch
39Coding convention clean-up
40
675e9664 41Revision 1.4 2000/11/30 07:12:50 alibrary
42Introducing new Rndm and QA classes
43
65fb704d 44Revision 1.3 2000/10/02 21:28:06 fca
45Removal of useless dependecies via forward declarations
46
94de3818 47Revision 1.2 2000/07/11 18:24:55 fca
48Coding convention corrections + few minor bug fixes
49
aee8290b 50Revision 1.1 2000/06/09 20:20:30 morsch
51Same class as previously in AliSimpleGen.cxx
52All coding rule violations except RS3 corrected (AM)
53
790bbabf 54*/
675e9664 55
56// Parameterisation of pi and K, eta and pt distributions
57// used for the ALICE TDRs.
58// eta: according to HIJING (shadowing + quenching)
59// pT : according to CDF measurement at 1.8 TeV
60// Author: andreas.morsch@cern.ch
61
62
790bbabf 63//Begin_Html
64/*
65<img src="picts/AliGeneratorClass.gif">
66</pre>
67<br clear=left>
68<font size=+2 color=red>
69<p>The responsible person for this module is
70<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
71</font>
72<pre>
73*/
74//End_Html
75// //
76///////////////////////////////////////////////////////////////////
77
78#include "AliGenHIJINGpara.h"
971816d4 79#include "AliGenEventHeader.h"
790bbabf 80#include "AliRun.h"
81#include "AliConst.h"
82#include "AliPDG.h"
83
971816d4 84#include <TF1.h>
85#include <TArrayF.h>
86
790bbabf 87ClassImp(AliGenHIJINGpara)
88
89AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
90{
91// copy constructor
92}
93
94//_____________________________________________________________________________
95static Double_t ptpi(Double_t *px, Double_t *)
96{
97 //
98 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
99 // POWER LAW FOR PT > 500 MEV
100 // MT SCALING BELOW (T=160 MEV)
101 //
102 const Double_t kp0 = 1.3;
103 const Double_t kxn = 8.28;
104 const Double_t kxlim=0.5;
105 const Double_t kt=0.160;
106 const Double_t kxmpi=0.139;
107 const Double_t kb=1.;
108 Double_t y, y1, xmpi2, ynorm, a;
109 Double_t x=*px;
110 //
111 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
112 xmpi2=kxmpi*kxmpi;
113 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
114 a=ynorm/y1;
115 if (x > kxlim)
116 y=a*TMath::Power(kp0/(kp0+x),kxn);
117 else
118 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
119 return y*x;
120}
121
122//_____________________________________________________________________________
123static Double_t ptscal(Double_t pt, Int_t np)
124{
125 // SCALING EN MASSE PAR RAPPORT A PTPI
126 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
127 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
128 // VALUE MESON/PI AT 5 GEV
129 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
130 np--;
131 Double_t f5=TMath::Power(((
132 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
133 Double_t fmax2=f5/kfmax[np];
134 // PIONS
135 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
136 Double_t fmtscal=TMath::Power(((
137 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
138 fmax2;
139 return fmtscal*ptpion;
140}
141
142//_____________________________________________________________________________
143static Double_t ptka( Double_t *px, Double_t *)
144{
145 //
146 // pt parametrisation for k
147 //
148 return ptscal(*px,2);
149}
150
151
152//_____________________________________________________________________________
153static Double_t etapic( Double_t *py, Double_t *)
154{
155 //
156 // eta parametrisation for pi
157 //
158 const Double_t ka1 = 4913.;
159 const Double_t ka2 = 1819.;
160 const Double_t keta1 = 0.22;
161 const Double_t keta2 = 3.66;
162 const Double_t kdeta1 = 1.47;
163 const Double_t kdeta2 = 1.51;
164 Double_t y=TMath::Abs(*py);
165 //
166 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
167 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
168 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
169}
170
171//_____________________________________________________________________________
172static Double_t etakac( Double_t *py, Double_t *)
173{
174 //
175 // eta parametrisation for ka
176 //
177 const Double_t ka1 = 497.6;
178 const Double_t ka2 = 215.6;
179 const Double_t keta1 = 0.79;
180 const Double_t keta2 = 4.09;
181 const Double_t kdeta1 = 1.54;
182 const Double_t kdeta2 = 1.40;
183 Double_t y=TMath::Abs(*py);
184 //
185 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
186 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
187 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
188}
189
190//_____________________________________________________________________________
191AliGenHIJINGpara::AliGenHIJINGpara()
192 :AliGenerator()
193{
194 //
195 // Default constructor
196 //
197 fPtpi = 0;
198 fPtka = 0;
199 fETApic = 0;
200 fETAkac = 0;
971816d4 201 SetCutVertexZ();
6b236b6f 202 SetPtRange();
790bbabf 203}
204
205//_____________________________________________________________________________
206AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
207 :AliGenerator(npart)
208{
209 //
210 // Standard constructor
211 //
212 fName="HIGINGpara";
213 fTitle="HIJING Parametrisation Particle Generator";
214 fPtpi = 0;
215 fPtka = 0;
216 fETApic = 0;
217 fETAkac = 0;
971816d4 218 SetCutVertexZ();
6b236b6f 219 SetPtRange();
790bbabf 220}
221
222//_____________________________________________________________________________
223AliGenHIJINGpara::~AliGenHIJINGpara()
224{
225 //
226 // Standard destructor
227 //
228 delete fPtpi;
229 delete fPtka;
230 delete fETApic;
231 delete fETAkac;
232}
233
234//_____________________________________________________________________________
235void AliGenHIJINGpara::Init()
236{
237 //
238 // Initialise the HIJING parametrisation
239 //
240 Float_t etaMin =-TMath::Log(TMath::Tan(
241 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
242 Float_t etaMax = -TMath::Log(TMath::Tan(
243 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2 244 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
245 fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf 246 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
247 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2 248
790bbabf 249 TF1 *etaPic0 = new TF1("etapic",&etapic,-7,7,0);
250 TF1 *etaKac0 = new TF1("etakac",&etakac,-7,7,0);
f25521b2 251
252 TF1 *ptPic0 = new TF1("ptpi",&ptpi,0.,15.,0);
253 TF1 *ptKac0 = new TF1("ptka",&ptka,0.,15.,0);
254
790bbabf 255 Float_t intETApi = etaPic0->Integral(-0.5, 0.5);
256 Float_t intETAka = etaKac0->Integral(-0.5, 0.5);
f25521b2 257 Float_t scalePi = 7316/(intETApi/1.5);
258 Float_t scaleKa = 684/(intETAka/2.0);
259
260// Fraction of events corresponding to the selected pt-range
261 Float_t intPt = (0.877*ptPic0->Integral(0, 15)+
262 0.123*ptKac0->Integral(0, 15));
263 Float_t intPtSel = (0.877*ptPic0->Integral(fPtMin, fPtMax)+
264 0.123*ptKac0->Integral(fPtMin, fPtMax));
265 Float_t ptFrac = intPtSel/intPt;
266
267// Fraction of events corresponding to the selected eta-range
790bbabf 268 Float_t intETASel = (scalePi*etaPic0->Integral(etaMin, etaMax)+
269 scaleKa*etaKac0->Integral(etaMin, etaMax));
f25521b2 270// Fraction of events corresponding to the selected phi-range
271 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
272
273 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
790bbabf 274
9e1a0ddb 275 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
276 ClassName(),100.*fParentWeight);
5b0e4c0f 277
278// Issue warning message if etaMin or etaMax are outside the alowed range
279// of the parametrization
280 if (etaMin < -8.001 || etaMax > 8.001) {
281 printf("\n \n WARNING FROM AliGenHIJINGPara !");
282 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
283 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
284 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
285 }
790bbabf 286}
287
288//_____________________________________________________________________________
289void AliGenHIJINGpara::Generate()
290{
291 //
292 // Generate one trigger
293 //
294
295
296 const Float_t kRaKpic=0.14;
297 const Float_t kBorne=1/(1+kRaKpic);
298 Float_t polar[3]= {0,0,0};
299 //
300 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
301 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
302 //
303 Float_t origin[3];
304 Float_t pt, pl, ptot;
305 Float_t phi, theta;
306 Float_t p[3];
307 Int_t i, part, nt, j;
308 //
309 TF1 *ptf;
310 TF1 *etaf;
311 //
312 Float_t random[6];
313 //
314 for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4 315
316 if(fVertexSmear == kPerEvent) {
317 Float_t dv[3];
318 dv[2] = 1.e10;
319 while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
320 Rndm(random,6);
321 for (j=0; j < 3; j++) {
322 dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
323 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
324 }
790bbabf 325 }
971816d4 326 for (j=0; j < 3; j++) origin[j] += dv[j];
327 } // if kPerEvent
328 TArrayF eventVertex;
329 eventVertex.Set(3);
330 eventVertex[0] = origin[0];
331 eventVertex[1] = origin[1];
332 eventVertex[2] = origin[2];
333
790bbabf 334 for(i=0;i<fNpart;i++) {
335 while(1) {
65fb704d 336 Rndm(random,3);
790bbabf 337 if(random[0]<kBorne) {
338 part=kPions[Int_t (random[1]*3)];
339 ptf=fPtpi;
340 etaf=fETApic;
341 } else {
342 part=kKaons[Int_t (random[1]*4)];
343 ptf=fPtka;
344 etaf=fETAkac;
345 }
346 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
347 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
348 if(theta<fThetaMin || theta>fThetaMax) continue;
349 pt=ptf->GetRandom();
350 pl=pt/TMath::Tan(theta);
351 ptot=TMath::Sqrt(pt*pt+pl*pl);
352 if(ptot<fPMin || ptot>fPMax) continue;
353 p[0]=pt*TMath::Cos(phi);
354 p[1]=pt*TMath::Sin(phi);
355 p[2]=pl;
aee8290b 356 if(fVertexSmear==kPerTrack) {
65fb704d 357 Rndm(random,6);
790bbabf 358 for (j=0;j<3;j++) {
359 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
360 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
361 }
362 }
a99cf51f 363 SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,nt,fParentWeight);
790bbabf 364 break;
365 }
366 }
971816d4 367// Header
368 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
369// Event Vertex
370 header->SetPrimaryVertex(eventVertex);
371 gAlice->SetGenEventHeader(header);
790bbabf 372}
373
374AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
375{
376// Assignment operator
377 return *this;
378}
379
6b236b6f 380void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
381 AliGenerator::SetPtRange(ptmin, ptmax);
382}
790bbabf 383