]> git.uio.no Git - u/mrichter/AliRoot.git/blame - EVGEN/AliGenHIJINGpara.cxx
git://git.uio.no / u / mrichter / AliRoot.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
Improved common vertex handling in cocktails.
[u/mrichter/AliRoot.git] / EVGEN / AliGenHIJINGpara.cxx
CommitLineData
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$Log$
c8f7f6f9 18Revision 1.21 2003/03/15 19:48:01 morsch
19AliDecayerPythia replaced by AliDecayer
20
2904363f 21Revision 1.20 2003/01/28 15:29:07 morsch
22Spelling in name corrected.
23
edbba5db 24Revision 1.19 2003/01/14 10:50:18 alibrary
25Cleanup of STEER coding conventions
26
116cbefd 27Revision 1.18 2002/12/11 11:58:11 morsch
28Bug in formula for pi0 energy for decay corrected.
29
56fcdfe6 30Revision 1.17 2002/12/10 17:44:57 morsch
31Correct mother child relation for pi0.
32
1e66857c 33Revision 1.16 2002/11/28 11:46:15 morsch
34Don't track pi0 if already decayed.
35
1ef5f15d 36Revision 1.15 2002/11/28 11:38:53 morsch
37Typo corrected.
38
7b33c00a 39Revision 1.14 2002/11/26 17:12:36 morsch
40Decay pi0 if requested.
41
2067f62c 42Revision 1.13 2002/10/14 14:55:35 hristov
43Merging the VirtualMC branch to the main development branch (HEAD)
44
b9d0a01d 45Revision 1.11.4.1 2002/07/24 08:56:28 alibrary
46Updating EVGEN on TVirtulaMC
47
48Revision 1.12 2002/06/19 06:56:34 hristov
49Memory leak corrected
50
aecf26a3 51Revision 1.11 2002/03/20 10:21:13 hristov
52Set fPtMax to 15 GeV in order to avoid some numerical problems
53
6b236b6f 54Revision 1.10 2001/10/15 16:44:46 morsch
55- Possibility for vertex distribution truncation.
56- Write mc header with vertex position.
57
971816d4 58Revision 1.9 2001/07/27 17:09:36 morsch
59Use local SetTrack, KeepTrack and SetHighWaterMark methods
60to delegate either to local stack or to stack owned by AliRun.
61(Piotr Skowronski, A.M.)
62
a99cf51f 63Revision 1.8 2001/07/20 11:03:58 morsch
64Issue warning message if used outside allowed eta range (-8 to 8).
65
5b0e4c0f 66Revision 1.7 2001/07/17 12:41:01 morsch
67- Calculation of fraction of event corresponding to selected pt-range corrected
68(R. Turrisi)
69- Parent weight corrected.
70
f25521b2 71Revision 1.6 2001/05/16 14:57:10 alibrary
72New files for folders and Stack
73
9e1a0ddb 74Revision 1.5 2000/12/21 16:24:06 morsch
75Coding convention clean-up
76
675e9664 77Revision 1.4 2000/11/30 07:12:50 alibrary
78Introducing new Rndm and QA classes
79
65fb704d 80Revision 1.3 2000/10/02 21:28:06 fca
81Removal of useless dependecies via forward declarations
82
94de3818 83Revision 1.2 2000/07/11 18:24:55 fca
84Coding convention corrections + few minor bug fixes
85
aee8290b 86Revision 1.1 2000/06/09 20:20:30 morsch
87Same class as previously in AliSimpleGen.cxx
88All coding rule violations except RS3 corrected (AM)
89
790bbabf 90*/
675e9664 91
92// Parameterisation of pi and K, eta and pt distributions
93// used for the ALICE TDRs.
94// eta: according to HIJING (shadowing + quenching)
95// pT : according to CDF measurement at 1.8 TeV
96// Author: andreas.morsch@cern.ch
97
98
790bbabf 99//Begin_Html
100/*
101<img src="picts/AliGeneratorClass.gif">
102</pre>
103<br clear=left>
104<font size=+2 color=red>
105<p>The responsible person for this module is
106<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
107</font>
108<pre>
109*/
110//End_Html
111// //
112///////////////////////////////////////////////////////////////////
113
971816d4 114#include <TArrayF.h>
2067f62c 115#include <TClonesArray.h>
116cbefd 116#include <TDatabasePDG.h>
117#include <TF1.h>
2067f62c 118#include <TParticle.h>
116cbefd 119#include <TPDGCode.h>
120
121#include "AliConst.h"
122#include "AliDecayer.h"
116cbefd 123#include "AliGenEventHeader.h"
124#include "AliGenHIJINGpara.h"
125#include "AliRun.h"
971816d4 126
790bbabf 127ClassImp(AliGenHIJINGpara)
128
129AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
130{
131// copy constructor
132}
133
134//_____________________________________________________________________________
135static Double_t ptpi(Double_t *px, Double_t *)
136{
137 //
138 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
139 // POWER LAW FOR PT > 500 MEV
140 // MT SCALING BELOW (T=160 MEV)
141 //
142 const Double_t kp0 = 1.3;
143 const Double_t kxn = 8.28;
144 const Double_t kxlim=0.5;
145 const Double_t kt=0.160;
146 const Double_t kxmpi=0.139;
147 const Double_t kb=1.;
148 Double_t y, y1, xmpi2, ynorm, a;
149 Double_t x=*px;
150 //
151 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
152 xmpi2=kxmpi*kxmpi;
153 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
154 a=ynorm/y1;
155 if (x > kxlim)
156 y=a*TMath::Power(kp0/(kp0+x),kxn);
157 else
158 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
159 return y*x;
160}
161
162//_____________________________________________________________________________
163static Double_t ptscal(Double_t pt, Int_t np)
164{
165 // SCALING EN MASSE PAR RAPPORT A PTPI
166 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
167 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
168 // VALUE MESON/PI AT 5 GEV
169 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
170 np--;
171 Double_t f5=TMath::Power(((
172 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
173 Double_t fmax2=f5/kfmax[np];
174 // PIONS
175 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
176 Double_t fmtscal=TMath::Power(((
177 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
178 fmax2;
179 return fmtscal*ptpion;
180}
181
182//_____________________________________________________________________________
183static Double_t ptka( Double_t *px, Double_t *)
184{
185 //
186 // pt parametrisation for k
187 //
188 return ptscal(*px,2);
189}
190
191
192//_____________________________________________________________________________
193static Double_t etapic( Double_t *py, Double_t *)
194{
195 //
196 // eta parametrisation for pi
197 //
198 const Double_t ka1 = 4913.;
199 const Double_t ka2 = 1819.;
200 const Double_t keta1 = 0.22;
201 const Double_t keta2 = 3.66;
202 const Double_t kdeta1 = 1.47;
203 const Double_t kdeta2 = 1.51;
204 Double_t y=TMath::Abs(*py);
205 //
206 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
207 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
208 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
209}
210
211//_____________________________________________________________________________
212static Double_t etakac( Double_t *py, Double_t *)
213{
214 //
215 // eta parametrisation for ka
216 //
217 const Double_t ka1 = 497.6;
218 const Double_t ka2 = 215.6;
219 const Double_t keta1 = 0.79;
220 const Double_t keta2 = 4.09;
221 const Double_t kdeta1 = 1.54;
222 const Double_t kdeta2 = 1.40;
223 Double_t y=TMath::Abs(*py);
224 //
225 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
226 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
227 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
228}
229
230//_____________________________________________________________________________
231AliGenHIJINGpara::AliGenHIJINGpara()
232 :AliGenerator()
233{
234 //
235 // Default constructor
236 //
1e66857c 237 fPtpi = 0;
238 fPtka = 0;
239 fETApic = 0;
240 fETAkac = 0;
241 fDecayer = 0;
242 fNt = -1;
971816d4 243 SetCutVertexZ();
6b236b6f 244 SetPtRange();
2067f62c 245 SetPi0Decays();
790bbabf 246}
247
248//_____________________________________________________________________________
249AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
250 :AliGenerator(npart)
251{
252 //
253 // Standard constructor
254 //
edbba5db 255 fName="HIJINGpara";
790bbabf 256 fTitle="HIJING Parametrisation Particle Generator";
1e66857c 257 fPtpi = 0;
258 fPtka = 0;
259 fETApic = 0;
260 fETAkac = 0;
261 fDecayer = 0;
262 fNt = -1;
971816d4 263 SetCutVertexZ();
6b236b6f 264 SetPtRange();
2067f62c 265 SetPi0Decays();
790bbabf 266}
267
268//_____________________________________________________________________________
269AliGenHIJINGpara::~AliGenHIJINGpara()
270{
271 //
272 // Standard destructor
273 //
274 delete fPtpi;
275 delete fPtka;
276 delete fETApic;
277 delete fETAkac;
278}
279
280//_____________________________________________________________________________
281void AliGenHIJINGpara::Init()
282{
283 //
284 // Initialise the HIJING parametrisation
285 //
286 Float_t etaMin =-TMath::Log(TMath::Tan(
287 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
288 Float_t etaMax = -TMath::Log(TMath::Tan(
289 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2 290 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
291 fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf 292 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
293 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2 294
aecf26a3 295 TF1 etaPic0("etapic",&etapic,-7,7,0);
296 TF1 etaKac0("etakac",&etakac,-7,7,0);
f25521b2 297
aecf26a3 298 TF1 ptPic0("ptpi",&ptpi,0.,15.,0);
299 TF1 ptKac0("ptka",&ptka,0.,15.,0);
f25521b2 300
aecf26a3 301 Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
302 Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
f25521b2 303 Float_t scalePi = 7316/(intETApi/1.5);
304 Float_t scaleKa = 684/(intETAka/2.0);
305
306// Fraction of events corresponding to the selected pt-range
aecf26a3 307 Float_t intPt = (0.877*ptPic0.Integral(0, 15)+
308 0.123*ptKac0.Integral(0, 15));
309 Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
310 0.123*ptKac0.Integral(fPtMin, fPtMax));
f25521b2 311 Float_t ptFrac = intPtSel/intPt;
312
313// Fraction of events corresponding to the selected eta-range
aecf26a3 314 Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
315 scaleKa*etaKac0.Integral(etaMin, etaMax));
f25521b2 316// Fraction of events corresponding to the selected phi-range
317 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
318
319 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
790bbabf 320
9e1a0ddb 321 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
322 ClassName(),100.*fParentWeight);
5b0e4c0f 323
324// Issue warning message if etaMin or etaMax are outside the alowed range
325// of the parametrization
326 if (etaMin < -8.001 || etaMax > 8.001) {
327 printf("\n \n WARNING FROM AliGenHIJINGPara !");
328 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
329 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
330 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
331 }
2067f62c 332//
333//
2904363f 334 if (fPi0Decays && gMC)
335 fDecayer = gMC->GetDecayer();
790bbabf 336}
337
2067f62c 338
790bbabf 339//_____________________________________________________________________________
340void AliGenHIJINGpara::Generate()
341{
342 //
343 // Generate one trigger
344 //
345
346
347 const Float_t kRaKpic=0.14;
348 const Float_t kBorne=1/(1+kRaKpic);
349 Float_t polar[3]= {0,0,0};
350 //
351 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
352 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
353 //
354 Float_t origin[3];
355 Float_t pt, pl, ptot;
356 Float_t phi, theta;
357 Float_t p[3];
1e66857c 358 Int_t i, part, j;
790bbabf 359 //
360 TF1 *ptf;
361 TF1 *etaf;
362 //
363 Float_t random[6];
364 //
365 for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4 366
367 if(fVertexSmear == kPerEvent) {
c8f7f6f9 368 Vertex();
369 for (j=0; j < 3; j++) origin[j] = fVertex[j];
971816d4 370 } // if kPerEvent
371 TArrayF eventVertex;
372 eventVertex.Set(3);
373 eventVertex[0] = origin[0];
374 eventVertex[1] = origin[1];
375 eventVertex[2] = origin[2];
376
790bbabf 377 for(i=0;i<fNpart;i++) {
378 while(1) {
65fb704d 379 Rndm(random,3);
790bbabf 380 if(random[0]<kBorne) {
381 part=kPions[Int_t (random[1]*3)];
382 ptf=fPtpi;
2067f62c 383 etaf=fETApic;
790bbabf 384 } else {
385 part=kKaons[Int_t (random[1]*4)];
386 ptf=fPtka;
387 etaf=fETAkac;
388 }
389 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
390 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
391 if(theta<fThetaMin || theta>fThetaMax) continue;
392 pt=ptf->GetRandom();
393 pl=pt/TMath::Tan(theta);
394 ptot=TMath::Sqrt(pt*pt+pl*pl);
395 if(ptot<fPMin || ptot>fPMax) continue;
396 p[0]=pt*TMath::Cos(phi);
397 p[1]=pt*TMath::Sin(phi);
398 p[2]=pl;
aee8290b 399 if(fVertexSmear==kPerTrack) {
65fb704d 400 Rndm(random,6);
790bbabf 401 for (j=0;j<3;j++) {
402 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
403 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
404 }
405 }
1ef5f15d 406 if (part == kPi0 && fPi0Decays){
2067f62c 407//
408// Decay pi0 if requested
1e66857c 409 SetTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
410 KeepTrack(fNt);
1ef5f15d 411 DecayPi0(origin, p);
412 } else {
1e66857c 413 SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
414 KeepTrack(fNt);
1ef5f15d 415 }
416
790bbabf 417 break;
418 }
1e66857c 419 SetHighWaterMark(fNt);
790bbabf 420 }
1e66857c 421//
422
971816d4 423// Header
424 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
425// Event Vertex
426 header->SetPrimaryVertex(eventVertex);
427 gAlice->SetGenEventHeader(header);
790bbabf 428}
429
430AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
431{
432// Assignment operator
433 return *this;
434}
435
6b236b6f 436void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
2067f62c 437 AliGenerator::SetPtRange(ptmin, ptmax);
6b236b6f 438}
790bbabf 439
2067f62c 440void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p)
441{
442//
443// Decay the pi0
444// and put decay products on the stack
445//
446 static TClonesArray *particles;
447 if(!particles) particles = new TClonesArray("TParticle",1000);
448//
449 const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
56fcdfe6 450 Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
2067f62c 451//
452// Decay the pi0
453 TLorentzVector pmom(p[0], p[1], p[2], e);
454 fDecayer->Decay(kPi0, &pmom);
56fcdfe6 455
2067f62c 456//
457// Put decay particles on the stack
458//
2067f62c 459 Float_t polar[3] = {0., 0., 0.};
460 Int_t np = fDecayer->ImportParticles(particles);
1e66857c 461 Int_t nt;
2067f62c 462 for (Int_t i = 1; i < np; i++)
463 {
7b33c00a 464 TParticle* iParticle = (TParticle *) particles->At(i);
465 p[0] = iParticle->Px();
466 p[1] = iParticle->Py();
467 p[2] = iParticle->Pz();
2067f62c 468 Int_t part = iParticle->GetPdgCode();
1e66857c 469
470 SetTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
471 KeepTrack(nt);
2067f62c 472 }
1e66857c 473 fNt = nt;
2067f62c 474}