1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 Revision 1.36 2002/02/08 16:50:50 morsch
19 Add name and title in constructor.
21 Revision 1.35 2002/01/21 10:02:40 morsch
23 Abort if too high rapidity causes numerical paroblem. User has to specify
26 Revision 1.34 2001/11/27 13:13:07 morsch
27 Maximum lifetime for long-lived particles to be put on the stack is parameter.
28 It can be set via SetMaximumLifetime(..).
30 Revision 1.33 2001/10/21 18:35:56 hristov
31 Several pointers were set to zero in the default constructors to avoid memory management problems
33 Revision 1.32 2001/07/27 17:09:36 morsch
34 Use local SetTrack, KeepTrack and SetHighWaterMark methods
35 to delegate either to local stack or to stack owned by AliRun.
36 (Piotr Skowronski, A.M.)
38 Revision 1.31 2001/07/13 10:58:54 morsch
39 - Some coded moved to AliGenMC
40 - Improved handling of secondary vertices.
42 Revision 1.30 2001/06/15 07:55:04 morsch
43 Put only first generation decay products on the stack.
45 Revision 1.29 2001/03/27 10:58:41 morsch
46 Initialize decayer before generation. Important if run inside cocktail.
48 Revision 1.28 2001/03/09 13:01:41 morsch
49 - enum constants for paramterisation type (particle family) moved to AliGen*lib.h
50 - use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
52 Revision 1.27 2001/02/02 15:21:10 morsch
53 Set high water mark after last particle.
54 Use Vertex() method for Vertex.
56 Revision 1.26 2000/12/21 16:24:06 morsch
57 Coding convention clean-up
59 Revision 1.25 2000/11/30 07:12:50 alibrary
60 Introducing new Rndm and QA classes
62 Revision 1.24 2000/10/18 19:11:27 hristov
63 Division by zero fixed
65 Revision 1.23 2000/10/02 21:28:06 fca
66 Removal of useless dependecies via forward declarations
68 Revision 1.22 2000/09/12 14:14:55 morsch
69 Call fDecayer->ForceDecay() at the beginning of Generate().
71 Revision 1.21 2000/09/08 15:39:01 morsch
72 Handle the case fForceDecay=all during the generation, i.e. select all secondaries.
74 Revision 1.20 2000/09/06 14:35:44 morsch
75 Use AliDecayerPythia for particle decays.
77 Revision 1.19 2000/07/11 18:24:56 fca
78 Coding convention corrections + few minor bug fixes
80 Revision 1.18 2000/06/29 21:08:27 morsch
81 All paramatrisation libraries derive from the pure virtual base class AliGenLib.
82 This allows to pass a pointer to a library directly to AliGenParam and avoids the
83 use of function pointers in Config.C.
85 Revision 1.17 2000/06/09 20:33:30 morsch
86 All coding rule violations except RS3 corrected
88 Revision 1.16 2000/05/02 07:51:31 morsch
89 - Control precision of pT sampling TF1::SetNpx(..)
90 - Correct initialisation of child-cuts in all constructors.
91 - Most coding rule violations corrected.
93 Revision 1.15 2000/04/03 15:42:12 morsch
94 Cuts on primary particles are separated from those on the decay products. Methods
95 SetChildMomentumRange, SetChildPtRange, SetChildPhiRange, SetChildThetaRange added.
97 Revision 1.14 1999/11/09 07:38:48 fca
98 Changes for compatibility with version 2.23 of ROOT
100 Revision 1.13 1999/11/04 11:30:31 fca
101 Correct the logics for SetForceDecay
103 Revision 1.12 1999/11/03 17:43:20 fca
104 New version from G.Martinez & A.Morsch
106 Revision 1.11 1999/09/29 09:24:14 fca
107 Introduction of the Copyright and cvs Log
113 // Class to generate particles from using paramtrized pT and y distributions.
114 // Distributions are obtained from pointer to object of type AliGenLib.
115 // (For example AliGenMUONlib)
116 // Decays are performed using Pythia.
117 // andreas.morsch@cern.ch
119 #include "AliGenParam.h"
120 #include "AliDecayerPythia.h"
121 #include "AliGenMUONlib.h"
123 #include <TParticle.h>
124 #include <TParticlePDG.h>
125 #include <TDatabasePDG.h>
126 #include <TLorentzVector.h>
130 ClassImp(AliGenParam)
132 //------------------------------------------------------------
136 <img src="picts/AliGenParam.gif">
140 //____________________________________________________________
141 //____________________________________________________________
142 AliGenParam::AliGenParam()
144 // Deafault constructor
151 // Set random number generator
158 AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library, Int_t param, char* tname):AliGenMC(npart)
160 // Constructor using number of particles parameterisation id and library
162 fTitle= "Particle Generator using pT and y parameterisation";
164 fPtParaFunc = Library->GetPt(param, tname);
165 fYParaFunc = Library->GetY (param, tname);
166 fIpParaFunc = Library->GetIp(param, tname);
175 // Set random number generator
179 //____________________________________________________________
181 AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(npart)
183 // Constructor using parameterisation id and number of particles
186 fTitle= "Particle Generator using pT and y parameterisation";
188 AliGenLib* pLibrary = new AliGenMUONlib();
190 fPtParaFunc = pLibrary->GetPt(param, tname);
191 fYParaFunc = pLibrary->GetY (param, tname);
192 fIpParaFunc = pLibrary->GetIp(param, tname);
199 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
202 SetChildMomentumRange();
205 SetChildThetaRange();
209 AliGenParam::AliGenParam(Int_t npart, Int_t param,
210 Double_t (*PtPara) (Double_t*, Double_t*),
211 Double_t (*YPara ) (Double_t* ,Double_t*),
212 Int_t (*IpPara) (TRandom *))
216 // Gines Martinez 1/10/99
218 fTitle= "Particle Generator using pT and y parameterisation";
220 fPtParaFunc = PtPara;
222 fIpParaFunc = IpPara;
229 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
232 SetChildMomentumRange();
235 SetChildThetaRange();
240 AliGenParam::AliGenParam(const AliGenParam & Param)
246 //____________________________________________________________
247 AliGenParam::~AliGenParam()
254 //____________________________________________________________
255 void AliGenParam::Init()
259 fDecayer = new AliDecayerPythia();
262 <img src="picts/AliGenParam.gif">
266 fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
267 // Set representation precision to 10 MeV
268 Int_t npx= Int_t((fPtMax-fPtMin)/fDeltaPt);
270 fPtPara->SetNpx(npx);
272 fYPara = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
273 TF1* ptPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
274 TF1* yPara = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
281 fdNdy0=fYParaFunc(&y1,&y2);
283 // Integral over generation region
284 Float_t intYS = yPara ->Integral(fYMin, fYMax);
285 Float_t intPt0 = ptPara->Integral(0,15);
286 Float_t intPtS = ptPara->Integral(fPtMin,fPtMax);
287 Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
288 if (fAnalog == kAnalog) {
289 fYWgt = intYS/fdNdy0;
290 fPtWgt = intPtS/intPt0;
291 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
293 fYWgt = intYS/fdNdy0;
294 fPtWgt = (fPtMax-fPtMin)/intPt0;
295 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
298 // particle decay related initialization
299 fDecayer->SetForceDecay(fForceDecay);
306 //____________________________________________________________
307 void AliGenParam::Generate()
310 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
311 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
312 // antineutrons in the the desired theta, phi and momentum windows;
313 // Gaussian smearing on the vertex is done if selected.
314 // The decay of heavy mesons is done using lujet,
315 // and the childern particle are tracked by GEANT
316 // However, light mesons are directly tracked by GEANT
317 // setting fForceDecay = nodecay (SetForceDecay(nodecay))
320 // Reinitialize decayer
323 Float_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking)
324 Float_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking)
325 Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
326 Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
328 och[3]; // Momentum, polarisation and origin of the children particles from lujet
333 static TClonesArray *particles;
335 if(!particles) particles = new TClonesArray("TParticle",1000);
337 static TDatabasePDG *pDataBase = new TDatabasePDG();
338 if(!pDataBase) pDataBase = new TDatabasePDG();
342 // Calculating vertex position per event
343 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
344 if(fVertexSmear==kPerEvent) {
346 for (j=0;j<3;j++) origin0[j]=fVertex[j];
351 // Generating fNpart particles
356 Int_t iPart = fIpParaFunc(fRandom);
357 fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
358 TParticlePDG *particle = pDataBase->GetParticle(iPart);
359 Float_t am = particle->Mass();
364 phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
367 ty = TMath::TanH(fYPara->GetRandom());
370 if (fAnalog == kAnalog) {
371 pt=fPtPara->GetRandom();
375 pt=fPtMin+random[1]*(fPtMax-fPtMin);
377 wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
378 wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
380 xmt=sqrt(pt*pt+am*am);
381 if (TMath::Abs(ty)==1.) {
384 "Division by 0: Please check you rapidity range !");
387 pl=xmt*ty/sqrt(1.-ty*ty);
388 theta=TMath::ATan2(pt,pl);
390 if(theta<fThetaMin || theta>fThetaMax) continue;
391 ptot=TMath::Sqrt(pt*pt+pl*pl);
393 if(ptot<fPMin || ptot>fPMax) continue;
395 p[0]=pt*TMath::Cos(phi);
396 p[1]=pt*TMath::Sin(phi);
398 if(fVertexSmear==kPerTrack) {
402 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
403 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
407 // Looking at fForceDecay :
408 // if fForceDecay != none Primary particle decays using
409 // AliPythia and children are tracked by GEANT
411 // if fForceDecay == none Primary particle is tracked by GEANT
412 // (In the latest, make sure that GEANT actually does all the decays you want)
415 if (fForceDecay != kNoDecay) {
416 // Using lujet to decay particle
417 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
418 TLorentzVector pmom(p[0], p[1], p[2], energy);
419 fDecayer->Decay(iPart,&pmom);
421 // select decay particles
422 Int_t np=fDecayer->ImportParticles(particles);
424 Int_t* pFlag = new Int_t[np];
425 Int_t* pParent = new Int_t[np];
426 Int_t* pSelected = new Int_t[np];
427 Int_t* trackIt = new Int_t[np];
429 for (i=0; i<np; i++) {
436 TParticle* iparticle = (TParticle *) particles->At(0);
438 for (i = 1; i<np ; i++) {
440 iparticle = (TParticle *) particles->At(i);
441 Int_t kf = iparticle->GetPdgCode();
442 Int_t ks = iparticle->GetStatusCode();
446 ipF = iparticle->GetFirstDaughter();
447 ipL = iparticle->GetLastDaughter();
448 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
452 // flag decay products of particles with long life-time (c tau > .3 mum)
455 // TParticlePDG *particle = pDataBase->GetParticle(kf);
457 Double_t lifeTime = fDecayer->GetLifetime(kf);
458 // Double_t mass = particle->Mass();
459 // Double_t width = particle->Width();
460 if (lifeTime > (Double_t) fMaxLifeTime) {
461 ipF = iparticle->GetFirstDaughter();
462 ipL = iparticle->GetLastDaughter();
463 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
472 if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll && trackIt[i])
475 pc[0]=iparticle->Px();
476 pc[1]=iparticle->Py();
477 pc[2]=iparticle->Pz();
478 Bool_t childok = KinematicSelection(iparticle, 1);
489 } // if child selection
491 } // decay particle loop
492 } // if decay products
495 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
499 SetTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp);
505 for (i = 1; i < np; i++) {
507 TParticle* iparticle = (TParticle *) particles->At(i);
508 Int_t kf = iparticle->GetPdgCode();
509 Int_t ipa = iparticle->GetFirstMother()-1;
511 och[0] = origin0[0]+iparticle->Vx()/10;
512 och[1] = origin0[1]+iparticle->Vy()/10;
513 och[2] = origin0[2]+iparticle->Vz()/10;
514 pc[0] = iparticle->Px();
515 pc[1] = iparticle->Py();
516 pc[2] = iparticle->Pz();
519 iparent = pParent[ipa];
523 SetTrack(fTrackIt*trackIt[i], iparent, kf,
525 0, kPDecay, nt, wgtch);
532 if (pFlag) delete[] pFlag;
533 if (pParent) delete[] pParent;
534 if (pSelected) delete[] pSelected;
535 if (trackIt) delete[] trackIt;
536 } // kinematic selection
537 else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
540 SetTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
546 SetHighWaterMark(nt);
549 AliGenParam& AliGenParam::operator=(const AliGenParam& rhs)
551 // Assignment operator