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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$Log$
edbba5db 18Revision 1.19 2003/01/14 10:50:18 alibrary
19Cleanup of STEER coding conventions
20
116cbefd 21Revision 1.18 2002/12/11 11:58:11 morsch
22Bug in formula for pi0 energy for decay corrected.
23
56fcdfe6 24Revision 1.17 2002/12/10 17:44:57 morsch
25Correct mother child relation for pi0.
26
1e66857c 27Revision 1.16 2002/11/28 11:46:15 morsch
28Don't track pi0 if already decayed.
29
1ef5f15d 30Revision 1.15 2002/11/28 11:38:53 morsch
31Typo corrected.
32
7b33c00a 33Revision 1.14 2002/11/26 17:12:36 morsch
34Decay pi0 if requested.
35
2067f62c 36Revision 1.13 2002/10/14 14:55:35 hristov
37Merging the VirtualMC branch to the main development branch (HEAD)
38
b9d0a01d 39Revision 1.11.4.1 2002/07/24 08:56:28 alibrary
40Updating EVGEN on TVirtulaMC
41
42Revision 1.12 2002/06/19 06:56:34 hristov
43Memory leak corrected
44
aecf26a3 45Revision 1.11 2002/03/20 10:21:13 hristov
46Set fPtMax to 15 GeV in order to avoid some numerical problems
47
6b236b6f 48Revision 1.10 2001/10/15 16:44:46 morsch
49- Possibility for vertex distribution truncation.
50- Write mc header with vertex position.
51
971816d4 52Revision 1.9 2001/07/27 17:09:36 morsch
53Use local SetTrack, KeepTrack and SetHighWaterMark methods
54to delegate either to local stack or to stack owned by AliRun.
55(Piotr Skowronski, A.M.)
56
a99cf51f 57Revision 1.8 2001/07/20 11:03:58 morsch
58Issue warning message if used outside allowed eta range (-8 to 8).
59
5b0e4c0f 60Revision 1.7 2001/07/17 12:41:01 morsch
61- Calculation of fraction of event corresponding to selected pt-range corrected
62(R. Turrisi)
63- Parent weight corrected.
64
f25521b2 65Revision 1.6 2001/05/16 14:57:10 alibrary
66New files for folders and Stack
67
9e1a0ddb 68Revision 1.5 2000/12/21 16:24:06 morsch
69Coding convention clean-up
70
675e9664 71Revision 1.4 2000/11/30 07:12:50 alibrary
72Introducing new Rndm and QA classes
73
65fb704d 74Revision 1.3 2000/10/02 21:28:06 fca
75Removal of useless dependecies via forward declarations
76
94de3818 77Revision 1.2 2000/07/11 18:24:55 fca
78Coding convention corrections + few minor bug fixes
79
aee8290b 80Revision 1.1 2000/06/09 20:20:30 morsch
81Same class as previously in AliSimpleGen.cxx
82All coding rule violations except RS3 corrected (AM)
83
790bbabf 84*/
675e9664 85
86// Parameterisation of pi and K, eta and pt distributions
87// used for the ALICE TDRs.
88// eta: according to HIJING (shadowing + quenching)
89// pT : according to CDF measurement at 1.8 TeV
90// Author: andreas.morsch@cern.ch
91
92
790bbabf 93//Begin_Html
94/*
95<img src="picts/AliGeneratorClass.gif">
96</pre>
97<br clear=left>
98<font size=+2 color=red>
99<p>The responsible person for this module is
100<a href="mailto:andreas.morsch@cern.ch">Andreas Morsch</a>.
101</font>
102<pre>
103*/
104//End_Html
105// //
106///////////////////////////////////////////////////////////////////
107
971816d4 108#include <TArrayF.h>
2067f62c 109#include <TClonesArray.h>
116cbefd 110#include <TDatabasePDG.h>
111#include <TF1.h>
2067f62c 112#include <TParticle.h>
116cbefd 113#include <TPDGCode.h>
114
115#include "AliConst.h"
116#include "AliDecayer.h"
117#include "AliDecayerPythia.h"
118#include "AliGenEventHeader.h"
119#include "AliGenHIJINGpara.h"
120#include "AliRun.h"
971816d4 121
790bbabf 122ClassImp(AliGenHIJINGpara)
123
124AliGenHIJINGpara::AliGenHIJINGpara(const AliGenHIJINGpara & para)
125{
126// copy constructor
127}
128
129//_____________________________________________________________________________
130static Double_t ptpi(Double_t *px, Double_t *)
131{
132 //
133 // PT-PARAMETERIZATION CDF, PRL 61(88) 1819
134 // POWER LAW FOR PT > 500 MEV
135 // MT SCALING BELOW (T=160 MEV)
136 //
137 const Double_t kp0 = 1.3;
138 const Double_t kxn = 8.28;
139 const Double_t kxlim=0.5;
140 const Double_t kt=0.160;
141 const Double_t kxmpi=0.139;
142 const Double_t kb=1.;
143 Double_t y, y1, xmpi2, ynorm, a;
144 Double_t x=*px;
145 //
146 y1=TMath::Power(kp0/(kp0+kxlim),kxn);
147 xmpi2=kxmpi*kxmpi;
148 ynorm=kb*(TMath::Exp(-sqrt(kxlim*kxlim+xmpi2)/kt));
149 a=ynorm/y1;
150 if (x > kxlim)
151 y=a*TMath::Power(kp0/(kp0+x),kxn);
152 else
153 y=kb*TMath::Exp(-sqrt(x*x+xmpi2)/kt);
154 return y*x;
155}
156
157//_____________________________________________________________________________
158static Double_t ptscal(Double_t pt, Int_t np)
159{
160 // SCALING EN MASSE PAR RAPPORT A PTPI
161 // MASS PI,K,ETA,RHO,OMEGA,ETA',PHI
162 const Double_t khm[10] = {.13957,.493,.5488,.769,.7826,.958,1.02,0,0,0};
163 // VALUE MESON/PI AT 5 GEV
164 const Double_t kfmax[10]={1.,0.3,0.55,1.0,1.0,1.0,1.0,0,0,0};
165 np--;
166 Double_t f5=TMath::Power(((
167 sqrt(100.018215)+2.)/(sqrt(100.+khm[np]*khm[np])+2.0)),12.3);
168 Double_t fmax2=f5/kfmax[np];
169 // PIONS
170 Double_t ptpion=100.*ptpi(&pt, (Double_t*) 0);
171 Double_t fmtscal=TMath::Power(((
172 sqrt(pt*pt+0.018215)+2.)/ (sqrt(pt*pt+khm[np]*khm[np])+2.0)),12.3)/
173 fmax2;
174 return fmtscal*ptpion;
175}
176
177//_____________________________________________________________________________
178static Double_t ptka( Double_t *px, Double_t *)
179{
180 //
181 // pt parametrisation for k
182 //
183 return ptscal(*px,2);
184}
185
186
187//_____________________________________________________________________________
188static Double_t etapic( Double_t *py, Double_t *)
189{
190 //
191 // eta parametrisation for pi
192 //
193 const Double_t ka1 = 4913.;
194 const Double_t ka2 = 1819.;
195 const Double_t keta1 = 0.22;
196 const Double_t keta2 = 3.66;
197 const Double_t kdeta1 = 1.47;
198 const Double_t kdeta2 = 1.51;
199 Double_t y=TMath::Abs(*py);
200 //
201 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
202 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
203 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
204}
205
206//_____________________________________________________________________________
207static Double_t etakac( Double_t *py, Double_t *)
208{
209 //
210 // eta parametrisation for ka
211 //
212 const Double_t ka1 = 497.6;
213 const Double_t ka2 = 215.6;
214 const Double_t keta1 = 0.79;
215 const Double_t keta2 = 4.09;
216 const Double_t kdeta1 = 1.54;
217 const Double_t kdeta2 = 1.40;
218 Double_t y=TMath::Abs(*py);
219 //
220 Double_t ex1 = (y-keta1)*(y-keta1)/(2*kdeta1*kdeta1);
221 Double_t ex2 = (y-keta2)*(y-keta2)/(2*kdeta2*kdeta2);
222 return ka1*TMath::Exp(-ex1)+ka2*TMath::Exp(-ex2);
223}
224
225//_____________________________________________________________________________
226AliGenHIJINGpara::AliGenHIJINGpara()
227 :AliGenerator()
228{
229 //
230 // Default constructor
231 //
1e66857c 232 fPtpi = 0;
233 fPtka = 0;
234 fETApic = 0;
235 fETAkac = 0;
236 fDecayer = 0;
237 fNt = -1;
971816d4 238 SetCutVertexZ();
6b236b6f 239 SetPtRange();
2067f62c 240 SetPi0Decays();
790bbabf 241}
242
243//_____________________________________________________________________________
244AliGenHIJINGpara::AliGenHIJINGpara(Int_t npart)
245 :AliGenerator(npart)
246{
247 //
248 // Standard constructor
249 //
edbba5db 250 fName="HIJINGpara";
790bbabf 251 fTitle="HIJING Parametrisation Particle Generator";
1e66857c 252 fPtpi = 0;
253 fPtka = 0;
254 fETApic = 0;
255 fETAkac = 0;
256 fDecayer = 0;
257 fNt = -1;
971816d4 258 SetCutVertexZ();
6b236b6f 259 SetPtRange();
2067f62c 260 SetPi0Decays();
790bbabf 261}
262
263//_____________________________________________________________________________
264AliGenHIJINGpara::~AliGenHIJINGpara()
265{
266 //
267 // Standard destructor
268 //
269 delete fPtpi;
270 delete fPtka;
271 delete fETApic;
272 delete fETAkac;
273}
274
275//_____________________________________________________________________________
276void AliGenHIJINGpara::Init()
277{
278 //
279 // Initialise the HIJING parametrisation
280 //
281 Float_t etaMin =-TMath::Log(TMath::Tan(
282 TMath::Min((Double_t)fThetaMax/2,TMath::Pi()/2-1.e-10)));
283 Float_t etaMax = -TMath::Log(TMath::Tan(
284 TMath::Max((Double_t)fThetaMin/2,1.e-10)));
f25521b2 285 fPtpi = new TF1("ptpi",&ptpi,0,20,0);
286 fPtka = new TF1("ptka",&ptka,0,20,0);
790bbabf 287 fETApic = new TF1("etapic",&etapic,etaMin,etaMax,0);
288 fETAkac = new TF1("etakac",&etakac,etaMin,etaMax,0);
f25521b2 289
aecf26a3 290 TF1 etaPic0("etapic",&etapic,-7,7,0);
291 TF1 etaKac0("etakac",&etakac,-7,7,0);
f25521b2 292
aecf26a3 293 TF1 ptPic0("ptpi",&ptpi,0.,15.,0);
294 TF1 ptKac0("ptka",&ptka,0.,15.,0);
f25521b2 295
aecf26a3 296 Float_t intETApi = etaPic0.Integral(-0.5, 0.5);
297 Float_t intETAka = etaKac0.Integral(-0.5, 0.5);
f25521b2 298 Float_t scalePi = 7316/(intETApi/1.5);
299 Float_t scaleKa = 684/(intETAka/2.0);
300
301// Fraction of events corresponding to the selected pt-range
aecf26a3 302 Float_t intPt = (0.877*ptPic0.Integral(0, 15)+
303 0.123*ptKac0.Integral(0, 15));
304 Float_t intPtSel = (0.877*ptPic0.Integral(fPtMin, fPtMax)+
305 0.123*ptKac0.Integral(fPtMin, fPtMax));
f25521b2 306 Float_t ptFrac = intPtSel/intPt;
307
308// Fraction of events corresponding to the selected eta-range
aecf26a3 309 Float_t intETASel = (scalePi*etaPic0.Integral(etaMin, etaMax)+
310 scaleKa*etaKac0.Integral(etaMin, etaMax));
f25521b2 311// Fraction of events corresponding to the selected phi-range
312 Float_t phiFrac = (fPhiMax-fPhiMin)/2/TMath::Pi();
313
314 fParentWeight = Float_t(fNpart)/(intETASel*ptFrac*phiFrac);
790bbabf 315
9e1a0ddb 316 printf("%s: The number of particles in the selected kinematic region corresponds to %f percent of a full event\n ",
317 ClassName(),100.*fParentWeight);
5b0e4c0f 318
319// Issue warning message if etaMin or etaMax are outside the alowed range
320// of the parametrization
321 if (etaMin < -8.001 || etaMax > 8.001) {
322 printf("\n \n WARNING FROM AliGenHIJINGPara !");
323 printf("\n YOU ARE USING THE PARAMETERISATION OUTSIDE ");
324 printf("\n THE ALLOWED PSEUDORAPIDITY RANGE (-8. - 8.)");
325 printf("\n YOUR LIMITS: %f %f \n \n ", etaMin, etaMax);
326 }
2067f62c 327//
328//
329 if (fPi0Decays) fDecayer = new AliDecayerPythia();
790bbabf 330}
331
2067f62c 332
790bbabf 333//_____________________________________________________________________________
334void AliGenHIJINGpara::Generate()
335{
336 //
337 // Generate one trigger
338 //
339
340
341 const Float_t kRaKpic=0.14;
342 const Float_t kBorne=1/(1+kRaKpic);
343 Float_t polar[3]= {0,0,0};
344 //
345 const Int_t kPions[3] = {kPi0, kPiPlus, kPiMinus};
346 const Int_t kKaons[4] = {kK0Long, kK0Short, kKPlus, kKMinus};
347 //
348 Float_t origin[3];
349 Float_t pt, pl, ptot;
350 Float_t phi, theta;
351 Float_t p[3];
1e66857c 352 Int_t i, part, j;
790bbabf 353 //
354 TF1 *ptf;
355 TF1 *etaf;
356 //
357 Float_t random[6];
358 //
359 for (j=0;j<3;j++) origin[j]=fOrigin[j];
971816d4 360
361 if(fVertexSmear == kPerEvent) {
362 Float_t dv[3];
363 dv[2] = 1.e10;
364 while(TMath::Abs(dv[2]) > fCutVertexZ*fOsigma[2]) {
365 Rndm(random,6);
366 for (j=0; j < 3; j++) {
367 dv[j] = fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
368 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
369 }
790bbabf 370 }
971816d4 371 for (j=0; j < 3; j++) origin[j] += dv[j];
372 } // if kPerEvent
373 TArrayF eventVertex;
374 eventVertex.Set(3);
375 eventVertex[0] = origin[0];
376 eventVertex[1] = origin[1];
377 eventVertex[2] = origin[2];
378
790bbabf 379 for(i=0;i<fNpart;i++) {
380 while(1) {
65fb704d 381 Rndm(random,3);
790bbabf 382 if(random[0]<kBorne) {
383 part=kPions[Int_t (random[1]*3)];
384 ptf=fPtpi;
2067f62c 385 etaf=fETApic;
790bbabf 386 } else {
387 part=kKaons[Int_t (random[1]*4)];
388 ptf=fPtka;
389 etaf=fETAkac;
390 }
391 phi=fPhiMin+random[2]*(fPhiMax-fPhiMin);
392 theta=2*TMath::ATan(TMath::Exp(-etaf->GetRandom()));
393 if(theta<fThetaMin || theta>fThetaMax) continue;
394 pt=ptf->GetRandom();
395 pl=pt/TMath::Tan(theta);
396 ptot=TMath::Sqrt(pt*pt+pl*pl);
397 if(ptot<fPMin || ptot>fPMax) continue;
398 p[0]=pt*TMath::Cos(phi);
399 p[1]=pt*TMath::Sin(phi);
400 p[2]=pl;
aee8290b 401 if(fVertexSmear==kPerTrack) {
65fb704d 402 Rndm(random,6);
790bbabf 403 for (j=0;j<3;j++) {
404 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
405 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
406 }
407 }
1ef5f15d 408 if (part == kPi0 && fPi0Decays){
2067f62c 409//
410// Decay pi0 if requested
1e66857c 411 SetTrack(0,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
412 KeepTrack(fNt);
1ef5f15d 413 DecayPi0(origin, p);
414 } else {
1e66857c 415 SetTrack(fTrackIt,-1,part,p,origin,polar,0,kPPrimary,fNt,fParentWeight);
416 KeepTrack(fNt);
1ef5f15d 417 }
418
790bbabf 419 break;
420 }
1e66857c 421 SetHighWaterMark(fNt);
790bbabf 422 }
1e66857c 423//
424
971816d4 425// Header
426 AliGenEventHeader* header = new AliGenEventHeader("HIJINGparam");
427// Event Vertex
428 header->SetPrimaryVertex(eventVertex);
429 gAlice->SetGenEventHeader(header);
790bbabf 430}
431
432AliGenHIJINGpara& AliGenHIJINGpara::operator=(const AliGenHIJINGpara& rhs)
433{
434// Assignment operator
435 return *this;
436}
437
6b236b6f 438void AliGenHIJINGpara::SetPtRange(Float_t ptmin, Float_t ptmax) {
2067f62c 439 AliGenerator::SetPtRange(ptmin, ptmax);
6b236b6f 440}
790bbabf 441
2067f62c 442void AliGenHIJINGpara::DecayPi0(Float_t* orig, Float_t * p)
443{
444//
445// Decay the pi0
446// and put decay products on the stack
447//
448 static TClonesArray *particles;
449 if(!particles) particles = new TClonesArray("TParticle",1000);
450//
451 const Float_t kMass = TDatabasePDG::Instance()->GetParticle(kPi0)->Mass();
56fcdfe6 452 Float_t e = TMath::Sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]+ kMass * kMass);
2067f62c 453//
454// Decay the pi0
455 TLorentzVector pmom(p[0], p[1], p[2], e);
456 fDecayer->Decay(kPi0, &pmom);
56fcdfe6 457
2067f62c 458//
459// Put decay particles on the stack
460//
2067f62c 461 Float_t polar[3] = {0., 0., 0.};
462 Int_t np = fDecayer->ImportParticles(particles);
1e66857c 463 Int_t nt;
2067f62c 464 for (Int_t i = 1; i < np; i++)
465 {
7b33c00a 466 TParticle* iParticle = (TParticle *) particles->At(i);
467 p[0] = iParticle->Px();
468 p[1] = iParticle->Py();
469 p[2] = iParticle->Pz();
2067f62c 470 Int_t part = iParticle->GetPdgCode();
1e66857c 471
472 SetTrack(fTrackIt, fNt, part, p, orig, polar, 0, kPDecay, nt, fParentWeight);
473 KeepTrack(nt);
2067f62c 474 }
1e66857c 475 fNt = nt;
2067f62c 476}