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Put only first generation decay products on the stack.
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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$Log$
18Revision 1.29 2001/03/27 10:58:41 morsch
19Initialize decayer before generation. Important if run inside cocktail.
20
21Revision 1.28 2001/03/09 13:01:41 morsch
22- enum constants for paramterisation type (particle family) moved to AliGen*lib.h
23- use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
24
25Revision 1.27 2001/02/02 15:21:10 morsch
26Set high water mark after last particle.
27Use Vertex() method for Vertex.
28
29Revision 1.26 2000/12/21 16:24:06 morsch
30Coding convention clean-up
31
32Revision 1.25 2000/11/30 07:12:50 alibrary
33Introducing new Rndm and QA classes
34
35Revision 1.24 2000/10/18 19:11:27 hristov
36Division by zero fixed
37
38Revision 1.23 2000/10/02 21:28:06 fca
39Removal of useless dependecies via forward declarations
40
41Revision 1.22 2000/09/12 14:14:55 morsch
42Call fDecayer->ForceDecay() at the beginning of Generate().
43
44Revision 1.21 2000/09/08 15:39:01 morsch
45Handle the case fForceDecay=all during the generation, i.e. select all secondaries.
46
47Revision 1.20 2000/09/06 14:35:44 morsch
48Use AliDecayerPythia for particle decays.
49
50Revision 1.19 2000/07/11 18:24:56 fca
51Coding convention corrections + few minor bug fixes
52
53Revision 1.18 2000/06/29 21:08:27 morsch
54All paramatrisation libraries derive from the pure virtual base class AliGenLib.
55This allows to pass a pointer to a library directly to AliGenParam and avoids the
56use of function pointers in Config.C.
57
58Revision 1.17 2000/06/09 20:33:30 morsch
59All coding rule violations except RS3 corrected
60
61Revision 1.16 2000/05/02 07:51:31 morsch
62- Control precision of pT sampling TF1::SetNpx(..)
63- Correct initialisation of child-cuts in all constructors.
64- Most coding rule violations corrected.
65
66Revision 1.15 2000/04/03 15:42:12 morsch
67Cuts on primary particles are separated from those on the decay products. Methods
68SetChildMomentumRange, SetChildPtRange, SetChildPhiRange, SetChildThetaRange added.
69
70Revision 1.14 1999/11/09 07:38:48 fca
71Changes for compatibility with version 2.23 of ROOT
72
73Revision 1.13 1999/11/04 11:30:31 fca
74Correct the logics for SetForceDecay
75
76Revision 1.12 1999/11/03 17:43:20 fca
77New version from G.Martinez & A.Morsch
78
79Revision 1.11 1999/09/29 09:24:14 fca
80Introduction of the Copyright and cvs Log
81
82*/
83
84#include "AliGenParam.h"
85#include "AliDecayerPythia.h"
86#include "AliGenMUONlib.h"
87#include "AliRun.h"
88#include <TParticle.h>
89#include <TParticlePDG.h>
90#include <TDatabasePDG.h>
91#include <TLorentzVector.h>
92
93#include <TF1.h>
94
95ClassImp(AliGenParam)
96
97//------------------------------------------------------------
98
99 //Begin_Html
100 /*
101 <img src="picts/AliGenParam.gif">
102 */
103 //End_Html
104
105//____________________________________________________________
106//____________________________________________________________
107AliGenParam::AliGenParam()
108{
109// Deafault constructor
110 fPtPara = 0;
111 fYPara = 0;
112 fParam = 0;
113 fAnalog = kAnalog;
114 SetCutOnChild();
115 SetChildMomentumRange();
116 SetChildPtRange();
117 SetChildPhiRange();
118 SetChildThetaRange();
119 SetDeltaPt();
120//
121// Set random number generator
122 sRandom = fRandom;
123}
124
125AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library, Int_t param, char* tname):AliGenerator(npart)
126{
127// Constructor using number of particles parameterisation id and library
128
129 fPtParaFunc = Library->GetPt(param, tname);
130 fYParaFunc = Library->GetY (param, tname);
131 fIpParaFunc = Library->GetIp(param, tname);
132
133 fPtPara = 0;
134 fYPara = 0;
135 fParam = param;
136 fAnalog = kAnalog;
137 fChildSelect.Set(5);
138 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
139 SetForceDecay();
140 SetCutOnChild();
141 SetChildMomentumRange();
142 SetChildPtRange();
143 SetChildPhiRange();
144 SetChildThetaRange();
145 SetDeltaPt();
146//
147// Set random number generator
148 sRandom = fRandom;
149}
150
151//____________________________________________________________
152
153AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenerator(npart)
154{
155// Constructor using parameterisation id and number of particles
156//
157 AliGenLib* pLibrary = new AliGenMUONlib();
158
159 fPtParaFunc = pLibrary->GetPt(param, tname);
160 fYParaFunc = pLibrary->GetY (param, tname);
161 fIpParaFunc = pLibrary->GetIp(param, tname);
162
163 fPtPara = 0;
164 fYPara = 0;
165 fParam = param;
166 fAnalog = kAnalog;
167 fChildSelect.Set(5);
168 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
169 SetForceDecay();
170 SetCutOnChild();
171 SetChildMomentumRange();
172 SetChildPtRange();
173 SetChildPhiRange();
174 SetChildThetaRange();
175 SetDeltaPt();
176}
177
178AliGenParam::AliGenParam(Int_t npart, Int_t param,
179 Double_t (*PtPara) (Double_t*, Double_t*),
180 Double_t (*YPara ) (Double_t* ,Double_t*),
181 Int_t (*IpPara) (TRandom *))
182 :AliGenerator(npart)
183{
184// Constructor
185// Gines Martinez 1/10/99
186 fPtParaFunc = PtPara;
187 fYParaFunc = YPara;
188 fIpParaFunc = IpPara;
189//
190 fPtPara = 0;
191 fYPara = 0;
192 fParam = param;
193 fAnalog = kAnalog;
194 fChildSelect.Set(5);
195 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
196 SetForceDecay();
197 SetCutOnChild();
198 SetChildMomentumRange();
199 SetChildPtRange();
200 SetChildPhiRange();
201 SetChildThetaRange();
202 SetDeltaPt();
203}
204
205
206AliGenParam::AliGenParam(const AliGenParam & Paramd)
207{
208// copy constructor
209}
210
211//____________________________________________________________
212AliGenParam::~AliGenParam()
213{
214// Destructor
215 delete fPtPara;
216 delete fYPara;
217}
218
219//____________________________________________________________
220void AliGenParam::Init()
221{
222// Initialisation
223
224 fDecayer = new AliDecayerPythia();
225 //Begin_Html
226 /*
227 <img src="picts/AliGenParam.gif">
228 */
229 //End_Html
230
231 fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
232// Set representation precision to 10 MeV
233 Int_t npx= Int_t((fPtMax-fPtMin)/fDeltaPt);
234
235 fPtPara->SetNpx(npx);
236
237 fYPara = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
238 TF1* ptPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
239 TF1* yPara = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
240
241//
242// dN/dy| y=0
243 Double_t y1=0;
244 Double_t y2=0;
245
246 fdNdy0=fYParaFunc(&y1,&y2);
247//
248// Integral over generation region
249 Float_t intYS = yPara ->Integral(fYMin, fYMax);
250 Float_t intPt0 = ptPara->Integral(0,15);
251 Float_t intPtS = ptPara->Integral(fPtMin,fPtMax);
252 Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
253 if (fAnalog == kAnalog) {
254 fYWgt = intYS/fdNdy0;
255 fPtWgt = intPtS/intPt0;
256 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
257 } else {
258 fYWgt = intYS/fdNdy0;
259 fPtWgt = (fPtMax-fPtMin)/intPt0;
260 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
261 }
262//
263// particle decay related initialization
264 fDecayer->SetForceDecay(fForceDecay);
265 fDecayer->Init();
266
267//
268 switch (fForceDecay)
269 {
270 case kSemiElectronic:
271 case kDiElectron:
272 case kBJpsiDiElectron:
273 case kBPsiPrimeDiElectron:
274 fChildSelect[0]=11;
275 break;
276 case kSemiMuonic:
277 case kDiMuon:
278 case kBJpsiDiMuon:
279 case kBPsiPrimeDiMuon:
280 fChildSelect[0]=13;
281 break;
282 case kPiToMu:
283 fChildSelect[0]=13;
284 break;
285 case kKaToMu:
286 fChildSelect[0]=13;
287 break;
288 case kHadronicD:
289// Implement me !!
290 break;
291 case kNoDecay:
292 break;
293 case kAll:
294 break;
295 }
296}
297
298//____________________________________________________________
299void AliGenParam::Generate()
300{
301//
302// Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
303// Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
304// antineutrons in the the desired theta, phi and momentum windows;
305// Gaussian smearing on the vertex is done if selected.
306// The decay of heavy mesons is done using lujet,
307// and the childern particle are tracked by GEANT
308// However, light mesons are directly tracked by GEANT
309// setting fForceDecay = nodecay (SetForceDecay(nodecay))
310//
311//
312// Reinitialize decayer
313 fDecayer->Init();
314//
315 Float_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking)
316 Float_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking)
317 Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
318 Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
319 Float_t p[3], pc[3],
320 och[3], pch[10][3]; // Momentum, polarisation and origin of the children particles from lujet
321 Float_t ty, xmt;
322 Int_t nt, i, j, kfch[10];
323 Float_t wgtp, wgtch;
324 Double_t dummy;
325 static TClonesArray *particles;
326 //
327 if(!particles) particles=new TClonesArray("TParticle",1000);
328
329 static TDatabasePDG *pDataBase = new TDatabasePDG();
330 if(!pDataBase) pDataBase = new TDatabasePDG();
331 //
332 Float_t random[6];
333
334// Calculating vertex position per event
335 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
336 if(fVertexSmear==kPerEvent) {
337// Rndm(random,6);
338// for (j=0;j<3;j++) {
339// origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
340// TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
341// TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
342// }
343// }
344 Vertex();
345 for (j=0;j<3;j++) origin0[j]=fVertex[j];
346 }
347
348 Int_t ipa=0;
349// Generating fNpart particles
350 while (ipa<fNpart) {
351 while(1) {
352//
353// particle type
354 Int_t iPart = fIpParaFunc(fRandom);
355 fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
356 TParticlePDG *particle = pDataBase->GetParticle(iPart);
357 Float_t am = particle->Mass();
358
359 Rndm(random,2);
360//
361// phi
362 phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
363//
364// y
365 ty=Float_t(TMath::TanH(fYPara->GetRandom()));
366//
367// pT
368 if (fAnalog == kAnalog) {
369 pt=fPtPara->GetRandom();
370 wgtp=fParentWeight;
371 wgtch=fChildWeight;
372 } else {
373 pt=fPtMin+random[1]*(fPtMax-fPtMin);
374 Double_t ptd=pt;
375 wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
376 wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
377 }
378 xmt=sqrt(pt*pt+am*am);
379 if (TMath::Abs(ty)==1) ty=0;
380 pl=xmt*ty/sqrt(1.-ty*ty);
381 theta=TMath::ATan2(pt,pl);
382// Cut on theta
383 if(theta<fThetaMin || theta>fThetaMax) continue;
384 ptot=TMath::Sqrt(pt*pt+pl*pl);
385// Cut on momentum
386 if(ptot<fPMin || ptot>fPMax) continue;
387 p[0]=pt*TMath::Cos(phi);
388 p[1]=pt*TMath::Sin(phi);
389 p[2]=pl;
390 if(fVertexSmear==kPerTrack) {
391 Rndm(random,6);
392 for (j=0;j<3;j++) {
393 origin0[j]=
394 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
395 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
396 }
397 }
398
399// Looking at fForceDecay :
400// if fForceDecay != none Primary particle decays using
401// AliPythia and children are tracked by GEANT
402//
403// if fForceDecay == none Primary particle is tracked by GEANT
404// (In the latest, make sure that GEANT actually does all the decays you want)
405//
406 if (fForceDecay != kNoDecay) {
407// Using lujet to decay particle
408 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
409 TLorentzVector pmom(p[0], p[1], p[2], energy);
410 fDecayer->Decay(iPart,&pmom);
411//
412// select decay particles
413 Int_t np=fDecayer->ImportParticles(particles);
414 Int_t ncsel=0;
415
416 if (np >1) {
417 TParticle* iparticle = (TParticle *) particles->At(0);
418 Int_t ipF = iparticle->GetFirstDaughter();
419 Int_t ipL = iparticle->GetLastDaughter();
420 for (i = ipF-1; i<ipL; i++) {
421 iparticle = (TParticle *) particles->At(i);
422 Int_t kf = iparticle->GetPdgCode();
423//
424// children
425 if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll)
426 {
427 pc[0]=iparticle->Px();
428 pc[1]=iparticle->Py();
429 pc[2]=iparticle->Pz();
430 och[0]=origin0[0]+iparticle->Vx()/10;
431 och[1]=origin0[1]+iparticle->Vy()/10;
432 och[2]=origin0[2]+iparticle->Vz()/10;
433 if (fCutOnChild) {
434 Float_t ptChild=TMath::Sqrt(pc[0]*pc[0]+pc[1]*pc[1]);
435 Float_t pChild=TMath::Sqrt(ptChild*ptChild+pc[2]*pc[2]);
436 Float_t thetaChild=TMath::ATan2(ptChild,pc[2]);
437 Float_t phiChild=TMath::ATan2(pc[1],pc[0]);
438 Bool_t childok =
439 ((ptChild > fChildPtMin && ptChild <fChildPtMax) &&
440 (pChild > fChildPMin && pChild <fChildPMax) &&
441 (thetaChild > fChildThetaMin && thetaChild <fChildThetaMax) &&
442 (phiChild > fChildPhiMin && phiChild <fChildPhiMax));
443 if(childok)
444 {
445 pch[ncsel][0]=pc[0];
446 pch[ncsel][1]=pc[1];
447 pch[ncsel][2]=pc[2];
448 kfch[ncsel]=kf;
449 ncsel++;
450 } else {
451 ncsel=-1;
452 break;
453 } // child kine cuts
454 } else {
455 pch[ncsel][0]=pc[0];
456 pch[ncsel][1]=pc[1];
457 pch[ncsel][2]=pc[2];
458 kfch[ncsel]=kf;
459 ncsel++;
460 } // if child selection
461 } // select muon
462 } // decay particle loop
463 } // if decay products
464
465 Int_t iparent;
466 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
467 ipa++;
468//
469// parent
470 gAlice->
471 SetTrack(0,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
472 iparent=nt;
473 gAlice->KeepTrack(nt);
474 for (i=0; i< ncsel; i++) {
475 gAlice->SetTrack(fTrackIt,iparent,kfch[i],
476 &pch[i][0],och,polar,
477 0,kPDecay,nt,wgtch);
478 gAlice->KeepTrack(nt);
479 }
480 } // Decays by Lujet
481 } // kinematic selection
482 else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
483 {
484 gAlice->
485 SetTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
486 ipa++;
487 }
488 break;
489 } // while
490 } // event loop
491 gAlice->SetHighWaterMark(nt);
492
493}
494
495Bool_t AliGenParam::ChildSelected(Int_t ip)
496{
497// True if particle is in list of selected children
498 for (Int_t i=0; i<5; i++)
499 {
500 if (fChildSelect[i]==ip) return kTRUE;
501 }
502 return kFALSE;
503}
504
505Bool_t AliGenParam::KinematicSelection(TParticle *particle)
506{
507// Perform kinematic cuts
508 Float_t px=particle->Px();
509 Float_t py=particle->Py();
510 Float_t pz=particle->Pz();
511//
512// momentum cut
513 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
514 if (p > fPMax || p < fPMin)
515 {
516// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
517 return kFALSE;
518 }
519 Float_t pt=TMath::Sqrt(px*px+py*py);
520
521//
522// theta cut
523 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
524 if (theta > fThetaMax || theta < fThetaMin)
525 {
526// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
527 return kFALSE;
528 }
529
530 return kTRUE;
531}
532
533
534AliGenParam& AliGenParam::operator=(const AliGenParam& rhs)
535{
536// Assignment operator
537 return *this;
538}
539
540
541