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 1.37 2002/04/17 10:20:44 morsch
19 Coding Rule violations corrected.
21 Revision 1.36 2002/02/08 16:50:50 morsch
22 Add name and title in constructor.
24 Revision 1.35 2002/01/21 10:02:40 morsch
26 Abort if too high rapidity causes numerical paroblem. User has to specify
29 Revision 1.34 2001/11/27 13:13:07 morsch
30 Maximum lifetime for long-lived particles to be put on the stack is parameter.
31 It can be set via SetMaximumLifetime(..).
33 Revision 1.33 2001/10/21 18:35:56 hristov
34 Several pointers were set to zero in the default constructors to avoid memory management problems
36 Revision 1.32 2001/07/27 17:09:36 morsch
37 Use local SetTrack, KeepTrack and SetHighWaterMark methods
38 to delegate either to local stack or to stack owned by AliRun.
39 (Piotr Skowronski, A.M.)
41 Revision 1.31 2001/07/13 10:58:54 morsch
42 - Some coded moved to AliGenMC
43 - Improved handling of secondary vertices.
45 Revision 1.30 2001/06/15 07:55:04 morsch
46 Put only first generation decay products on the stack.
48 Revision 1.29 2001/03/27 10:58:41 morsch
49 Initialize decayer before generation. Important if run inside cocktail.
51 Revision 1.28 2001/03/09 13:01:41 morsch
52 - enum constants for paramterisation type (particle family) moved to AliGen*lib.h
53 - use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
55 Revision 1.27 2001/02/02 15:21:10 morsch
56 Set high water mark after last particle.
57 Use Vertex() method for Vertex.
59 Revision 1.26 2000/12/21 16:24:06 morsch
60 Coding convention clean-up
62 Revision 1.25 2000/11/30 07:12:50 alibrary
63 Introducing new Rndm and QA classes
65 Revision 1.24 2000/10/18 19:11:27 hristov
66 Division by zero fixed
68 Revision 1.23 2000/10/02 21:28:06 fca
69 Removal of useless dependecies via forward declarations
71 Revision 1.22 2000/09/12 14:14:55 morsch
72 Call fDecayer->ForceDecay() at the beginning of Generate().
74 Revision 1.21 2000/09/08 15:39:01 morsch
75 Handle the case fForceDecay=all during the generation, i.e. select all secondaries.
77 Revision 1.20 2000/09/06 14:35:44 morsch
78 Use AliDecayerPythia for particle decays.
80 Revision 1.19 2000/07/11 18:24:56 fca
81 Coding convention corrections + few minor bug fixes
83 Revision 1.18 2000/06/29 21:08:27 morsch
84 All paramatrisation libraries derive from the pure virtual base class AliGenLib.
85 This allows to pass a pointer to a library directly to AliGenParam and avoids the
86 use of function pointers in Config.C.
88 Revision 1.17 2000/06/09 20:33:30 morsch
89 All coding rule violations except RS3 corrected
91 Revision 1.16 2000/05/02 07:51:31 morsch
92 - Control precision of pT sampling TF1::SetNpx(..)
93 - Correct initialisation of child-cuts in all constructors.
94 - Most coding rule violations corrected.
96 Revision 1.15 2000/04/03 15:42:12 morsch
97 Cuts on primary particles are separated from those on the decay products. Methods
98 SetChildMomentumRange, SetChildPtRange, SetChildPhiRange, SetChildThetaRange added.
100 Revision 1.14 1999/11/09 07:38:48 fca
101 Changes for compatibility with version 2.23 of ROOT
103 Revision 1.13 1999/11/04 11:30:31 fca
104 Correct the logics for SetForceDecay
106 Revision 1.12 1999/11/03 17:43:20 fca
107 New version from G.Martinez & A.Morsch
109 Revision 1.11 1999/09/29 09:24:14 fca
110 Introduction of the Copyright and cvs Log
116 // Class to generate particles from using paramtrized pT and y distributions.
117 // Distributions are obtained from pointer to object of type AliGenLib.
118 // (For example AliGenMUONlib)
119 // Decays are performed using Pythia.
120 // andreas.morsch@cern.ch
122 #include "AliGenParam.h"
123 #include "AliDecayerPythia.h"
124 #include "AliGenMUONlib.h"
126 #include <TParticle.h>
127 #include <TParticlePDG.h>
128 #include <TDatabasePDG.h>
129 #include <TLorentzVector.h>
133 ClassImp(AliGenParam)
135 //------------------------------------------------------------
139 <img src="picts/AliGenParam.gif">
143 //____________________________________________________________
144 //____________________________________________________________
145 AliGenParam::AliGenParam()
147 // Deafault constructor
154 // Set random number generator
161 AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library, Int_t param, char* tname):AliGenMC(npart)
163 // Constructor using number of particles parameterisation id and library
165 fTitle= "Particle Generator using pT and y parameterisation";
167 fPtParaFunc = Library->GetPt(param, tname);
168 fYParaFunc = Library->GetY (param, tname);
169 fIpParaFunc = Library->GetIp(param, tname);
178 // Set random number generator
182 //____________________________________________________________
184 AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(npart)
186 // Constructor using parameterisation id and number of particles
189 fTitle= "Particle Generator using pT and y parameterisation";
191 AliGenLib* pLibrary = new AliGenMUONlib();
193 fPtParaFunc = pLibrary->GetPt(param, tname);
194 fYParaFunc = pLibrary->GetY (param, tname);
195 fIpParaFunc = pLibrary->GetIp(param, tname);
202 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
205 SetChildMomentumRange();
208 SetChildThetaRange();
212 AliGenParam::AliGenParam(Int_t npart, Int_t param,
213 Double_t (*PtPara) (Double_t*, Double_t*),
214 Double_t (*YPara ) (Double_t* ,Double_t*),
215 Int_t (*IpPara) (TRandom *))
219 // Gines Martinez 1/10/99
221 fTitle= "Particle Generator using pT and y parameterisation";
223 fPtParaFunc = PtPara;
225 fIpParaFunc = IpPara;
232 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
235 SetChildMomentumRange();
238 SetChildThetaRange();
243 AliGenParam::AliGenParam(const AliGenParam & Param)
249 //____________________________________________________________
250 AliGenParam::~AliGenParam()
257 //____________________________________________________________
258 void AliGenParam::Init()
262 fDecayer = new AliDecayerPythia();
265 <img src="picts/AliGenParam.gif">
269 fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
270 // Set representation precision to 10 MeV
271 Int_t npx= Int_t((fPtMax-fPtMin)/fDeltaPt);
273 fPtPara->SetNpx(npx);
275 fYPara = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
276 TF1* ptPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
277 TF1* yPara = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
284 fdNdy0=fYParaFunc(&y1,&y2);
286 // Integral over generation region
287 Float_t intYS = yPara ->Integral(fYMin, fYMax);
288 Float_t intPt0 = ptPara->Integral(0,15);
289 Float_t intPtS = ptPara->Integral(fPtMin,fPtMax);
290 Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
291 if (fAnalog == kAnalog) {
292 fYWgt = intYS/fdNdy0;
293 fPtWgt = intPtS/intPt0;
294 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
296 fYWgt = intYS/fdNdy0;
297 fPtWgt = (fPtMax-fPtMin)/intPt0;
298 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
301 // particle decay related initialization
302 fDecayer->SetForceDecay(fForceDecay);
309 //____________________________________________________________
310 void AliGenParam::Generate()
313 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
314 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
315 // antineutrons in the the desired theta, phi and momentum windows;
316 // Gaussian smearing on the vertex is done if selected.
317 // The decay of heavy mesons is done using lujet,
318 // and the childern particle are tracked by GEANT
319 // However, light mesons are directly tracked by GEANT
320 // setting fForceDecay = nodecay (SetForceDecay(nodecay))
323 // Reinitialize decayer
326 Float_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking)
327 Float_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking)
328 Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
329 Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
331 och[3]; // Momentum, polarisation and origin of the children particles from lujet
336 static TClonesArray *particles;
338 if(!particles) particles = new TClonesArray("TParticle",1000);
340 static TDatabasePDG *pDataBase = new TDatabasePDG();
341 if(!pDataBase) pDataBase = new TDatabasePDG();
345 // Calculating vertex position per event
346 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
347 if(fVertexSmear==kPerEvent) {
349 for (j=0;j<3;j++) origin0[j]=fVertex[j];
354 // Generating fNpart particles
359 Int_t iPart = fIpParaFunc(fRandom);
360 fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
361 TParticlePDG *particle = pDataBase->GetParticle(iPart);
362 Float_t am = particle->Mass();
367 phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
370 ty = TMath::TanH(fYPara->GetRandom());
373 if (fAnalog == kAnalog) {
374 pt=fPtPara->GetRandom();
378 pt=fPtMin+random[1]*(fPtMax-fPtMin);
380 wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
381 wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
383 xmt=sqrt(pt*pt+am*am);
384 if (TMath::Abs(ty)==1.) {
387 "Division by 0: Please check you rapidity range !");
390 pl=xmt*ty/sqrt(1.-ty*ty);
391 theta=TMath::ATan2(pt,pl);
393 if(theta<fThetaMin || theta>fThetaMax) continue;
394 ptot=TMath::Sqrt(pt*pt+pl*pl);
396 if(ptot<fPMin || ptot>fPMax) continue;
398 p[0]=pt*TMath::Cos(phi);
399 p[1]=pt*TMath::Sin(phi);
401 if(fVertexSmear==kPerTrack) {
405 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
406 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
410 // Looking at fForceDecay :
411 // if fForceDecay != none Primary particle decays using
412 // AliPythia and children are tracked by GEANT
414 // if fForceDecay == none Primary particle is tracked by GEANT
415 // (In the latest, make sure that GEANT actually does all the decays you want)
418 if (fForceDecay != kNoDecay) {
419 // Using lujet to decay particle
420 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
421 TLorentzVector pmom(p[0], p[1], p[2], energy);
422 fDecayer->Decay(iPart,&pmom);
424 // select decay particles
425 Int_t np=fDecayer->ImportParticles(particles);
427 // Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
428 if (fGeometryAcceptance)
429 if (!CheckAcceptanceGeometry(np,particles)) continue;
432 Int_t* pFlag = new Int_t[np];
433 Int_t* pParent = new Int_t[np];
434 Int_t* pSelected = new Int_t[np];
435 Int_t* trackIt = new Int_t[np];
437 for (i=0; i<np; i++) {
444 TParticle* iparticle = (TParticle *) particles->At(0);
446 for (i = 1; i<np ; i++) {
448 iparticle = (TParticle *) particles->At(i);
449 Int_t kf = iparticle->GetPdgCode();
450 Int_t ks = iparticle->GetStatusCode();
454 ipF = iparticle->GetFirstDaughter();
455 ipL = iparticle->GetLastDaughter();
456 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
460 // flag decay products of particles with long life-time (c tau > .3 mum)
463 // TParticlePDG *particle = pDataBase->GetParticle(kf);
465 Double_t lifeTime = fDecayer->GetLifetime(kf);
466 // Double_t mass = particle->Mass();
467 // Double_t width = particle->Width();
468 if (lifeTime > (Double_t) fMaxLifeTime) {
469 ipF = iparticle->GetFirstDaughter();
470 ipL = iparticle->GetLastDaughter();
471 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
480 if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll && trackIt[i])
483 pc[0]=iparticle->Px();
484 pc[1]=iparticle->Py();
485 pc[2]=iparticle->Pz();
486 Bool_t childok = KinematicSelection(iparticle, 1);
497 } // if child selection
499 } // decay particle loop
500 } // if decay products
503 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
507 SetTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp);
513 for (i = 1; i < np; i++) {
515 TParticle* iparticle = (TParticle *) particles->At(i);
516 Int_t kf = iparticle->GetPdgCode();
517 Int_t ipa = iparticle->GetFirstMother()-1;
519 och[0] = origin0[0]+iparticle->Vx()/10;
520 och[1] = origin0[1]+iparticle->Vy()/10;
521 och[2] = origin0[2]+iparticle->Vz()/10;
522 pc[0] = iparticle->Px();
523 pc[1] = iparticle->Py();
524 pc[2] = iparticle->Pz();
527 iparent = pParent[ipa];
532 SetTrack(fTrackIt*trackIt[i], iparent, kf,
534 0, kPDecay, nt, wgtch);
541 if (pFlag) delete[] pFlag;
542 if (pParent) delete[] pParent;
543 if (pSelected) delete[] pSelected;
544 if (trackIt) delete[] trackIt;
545 } // kinematic selection
546 else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
549 SetTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
555 SetHighWaterMark(nt);
558 AliGenParam& AliGenParam::operator=(const AliGenParam& rhs)
560 // Assignment operator