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 // Class to generate particles from using paramtrized pT and y distributions.
19 // Distributions are obtained from pointer to object of type AliGenLib.
20 // (For example AliGenMUONlib)
21 // Decays are performed using Pythia.
22 // andreas.morsch@cern.ch
25 #include <TClonesArray.h>
26 #include <TDatabasePDG.h>
29 #include <TLorentzVector.h>
31 #include <TParticle.h>
32 #include <TParticlePDG.h>
34 #include <TVirtualMC.h>
36 #include "AliDecayer.h"
37 #include "AliGenMUONlib.h"
38 #include "AliGenParam.h"
41 #include "AliGenEventHeader.h"
45 //------------------------------------------------------------
49 <img src="picts/AliGenParam.gif">
53 //____________________________________________________________
54 AliGenParam::AliGenParam()
73 // Default constructor
75 //____________________________________________________________
76 AliGenParam::AliGenParam(Int_t npart, const AliGenLib * Library, Int_t param, const char* tname)
78 fPtParaFunc(Library->GetPt(param, tname)),
79 fYParaFunc (Library->GetY (param, tname)),
80 fIpParaFunc(Library->GetIp(param, tname)),
81 fV2ParaFunc(Library->GetV2(param, tname)),
96 // Constructor using number of particles parameterisation id and library
98 fTitle= "Particle Generator using pT and y parameterisation";
102 //____________________________________________________________
103 AliGenParam::AliGenParam(Int_t npart, Int_t param, const char* tname, const char* name):
123 // Constructor using parameterisation id and number of particles
126 fTitle= "Particle Generator using pT and y parameterisation";
128 AliGenLib* pLibrary = new AliGenMUONlib();
129 fPtParaFunc = pLibrary->GetPt(param, tname);
130 fYParaFunc = pLibrary->GetY (param, tname);
131 fIpParaFunc = pLibrary->GetIp(param, tname);
132 fV2ParaFunc = pLibrary->GetV2(param, tname);
136 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
139 SetChildMomentumRange();
142 SetChildThetaRange();
144 //____________________________________________________________
146 AliGenParam::AliGenParam(Int_t npart, Int_t param,
147 Double_t (*PtPara) (const Double_t*, const Double_t*),
148 Double_t (*YPara ) (const Double_t* ,const Double_t*),
149 Double_t (*V2Para) (const Double_t* ,const Double_t*),
150 Int_t (*IpPara) (TRandom *))
172 // Gines Martinez 1/10/99
174 fTitle= "Particle Generator using pT and y parameterisation";
178 for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
181 SetChildMomentumRange();
184 SetChildThetaRange();
187 //____________________________________________________________
188 AliGenParam::~AliGenParam()
197 //____________________________________________________________
198 void AliGenParam::Init()
202 if (gMC) fDecayer = gMC->GetDecayer();
205 <img src="picts/AliGenParam.gif">
209 snprintf(name, 256, "pt-parameterisation for %s", GetName());
211 if (fPtPara) fPtPara->Delete();
212 fPtPara = new TF1(name, fPtParaFunc, fPtMin, fPtMax,0);
213 gROOT->GetListOfFunctions()->Remove(fPtPara);
214 // Set representation precision to 10 MeV
215 Int_t npx= Int_t((fPtMax - fPtMin) / fDeltaPt);
217 fPtPara->SetNpx(npx);
219 snprintf(name, 256, "y-parameterisation for %s", GetName());
220 if (fYPara) fYPara->Delete();
221 fYPara = new TF1(name, fYParaFunc, fYMin, fYMax, 0);
222 gROOT->GetListOfFunctions()->Remove(fYPara);
224 snprintf(name, 256, "v2-parameterisation for %s", GetName());
225 if (fV2Para) fV2Para->Delete();
226 fV2Para = new TF1(name, fV2ParaFunc, fPtMin, fPtMax, 0);
227 // fV2Para = new TF1(name, "2*[0]/(1+TMath::Exp([1]*([2]-x)))-[0]", fPtMin, fPtMax);
228 // fV2Para->SetParameter(0, 0.236910);
229 // fV2Para->SetParameter(1, 1.71122);
230 // fV2Para->SetParameter(2, 0.0827617);
231 //gROOT->GetListOfFunctions()->Remove(fV2Para); //TR: necessary?
233 snprintf(name, 256, "dNdPhi for %s", GetName());
234 if (fdNdPhi) fdNdPhi->Delete();
235 fdNdPhi = new TF1(name, "1+2*[0]*TMath::Cos(2*(x-[1]))", fPhiMin, fPhiMax);
236 //gROOT->GetListOfFunctions()->Remove(fdNdPhi); //TR: necessary?
238 snprintf(name, 256, "pt-for-%s", GetName());
239 TF1 ptPara(name ,fPtParaFunc, 0, 15, 0);
240 snprintf(name, 256, "y-for-%s", GetName());
241 TF1 yPara(name, fYParaFunc, -6, 6, 0);
248 fdNdy0=fYParaFunc(&y1,&y2);
250 // Integral over generation region
251 Float_t intYS = yPara.Integral(fYMin, fYMax,(Double_t*) 0x0,1.e-6);
252 Float_t intPt0 = ptPara.Integral(0,15,(Double_t *) 0x0,1.e-6);
253 Float_t intPtS = ptPara.Integral(fPtMin,fPtMax,(Double_t*) 0x0,1.e-6);
254 Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi(); //TR: should probably be done differently in case of anisotropic phi...
255 if (fAnalog == kAnalog) {
256 fYWgt = intYS/fdNdy0;
257 fPtWgt = intPtS/intPt0;
258 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
260 fYWgt = intYS/fdNdy0;
261 fPtWgt = (fPtMax-fPtMin)/intPt0;
262 fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
265 // particle decay related initialization
266 fDecayer->SetForceDecay(fForceDecay);
273 //____________________________________________________________
274 void AliGenParam::Generate()
277 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
278 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
279 // antineutrons in the the desired theta, phi and momentum windows;
280 // Gaussian smearing on the vertex is done if selected.
281 // The decay of heavy mesons is done using lujet,
282 // and the childern particle are tracked by GEANT
283 // However, light mesons are directly tracked by GEANT
284 // setting fForceDecay = nodecay (SetForceDecay(nodecay))
287 // Reinitialize decayer
288 fDecayer->SetForceDecay(fForceDecay);
292 Float_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking)
293 Float_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking)
294 Float_t time0; // Time0 of the generated parent particle
295 Float_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
296 Float_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
298 och[3]; // Momentum, polarisation and origin of the children particles from lujet
303 static TClonesArray *particles;
305 if(!particles) particles = new TClonesArray("TParticle",1000);
307 TDatabasePDG *pDataBase = TDatabasePDG::Instance();
311 // Calculating vertex position per event
312 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
314 if(fVertexSmear==kPerEvent) {
316 for (j=0;j<3;j++) origin0[j]=fVertex[j];
322 // Generating fNpart particles
329 Int_t iPart = fIpParaFunc(fRandom);
330 fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
331 TParticlePDG *particle = pDataBase->GetParticle(iPart);
332 Float_t am = particle->Mass();
337 ty = TMath::TanH(fYPara->GetRandom());
340 if (fAnalog == kAnalog) {
341 pt=fPtPara->GetRandom();
345 pt=fPtMin+random[1]*(fPtMax-fPtMin);
347 wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
348 wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
350 xmt=sqrt(pt*pt+am*am);
351 if (TMath::Abs(ty)==1.) {
354 "Division by 0: Please check you rapidity range !");
359 // phi=fEvPlane; //align first particle of each event with event plane
361 double v2 = fV2Para->Eval(pt);
362 fdNdPhi->SetParameter(0,v2);
363 fdNdPhi->SetParameter(1,fEvPlane);
364 phi=fdNdPhi->GetRandom();
367 pl=xmt*ty/sqrt((1.-ty)*(1.+ty));
368 theta=TMath::ATan2(pt,pl);
370 if(theta<fThetaMin || theta>fThetaMax) continue;
371 ptot=TMath::Sqrt(pt*pt+pl*pl);
373 if(ptot<fPMin || ptot>fPMax) continue;
375 p[0]=pt*TMath::Cos(phi);
376 p[1]=pt*TMath::Sin(phi);
378 if(fVertexSmear==kPerTrack) {
382 fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
383 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
386 time0 = fTimeOrigin + fOsigma[2]/TMath::Ccgs()*
387 TMath::Cos(2*random[0]*TMath::Pi())*
388 TMath::Sqrt(-2*TMath::Log(random[1]));
391 // Looking at fForceDecay :
392 // if fForceDecay != none Primary particle decays using
393 // AliPythia and children are tracked by GEANT
395 // if fForceDecay == none Primary particle is tracked by GEANT
396 // (In the latest, make sure that GEANT actually does all the decays you want)
398 Bool_t decayed = kFALSE;
401 if (fForceDecay != kNoDecay) {
402 // Using lujet to decay particle
403 Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
404 TLorentzVector pmom(p[0], p[1], p[2], energy);
405 fDecayer->Decay(iPart,&pmom);
407 // select decay particles
408 Int_t np=fDecayer->ImportParticles(particles);
410 // Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
411 if (fGeometryAcceptance)
412 if (!CheckAcceptanceGeometry(np,particles)) continue;
414 Int_t* pFlag = new Int_t[np];
415 Int_t* pParent = new Int_t[np];
416 Int_t* pSelected = new Int_t[np];
417 Int_t* trackIt = new Int_t[np];
419 for (i=0; i<np; i++) {
427 TParticle* iparticle = 0;
429 for (i = 1; i<np ; i++) {
431 iparticle = (TParticle *) particles->At(i);
432 Int_t kf = iparticle->GetPdgCode();
433 Int_t ks = iparticle->GetStatusCode();
437 ipF = iparticle->GetFirstDaughter();
438 ipL = iparticle->GetLastDaughter();
439 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
443 // flag decay products of particles with long life-time (c tau > .3 mum)
446 // TParticlePDG *particle = pDataBase->GetParticle(kf);
448 Double_t lifeTime = fDecayer->GetLifetime(kf);
449 // Double_t mass = particle->Mass();
450 // Double_t width = particle->Width();
451 if (lifeTime > (Double_t) fMaxLifeTime) {
452 ipF = iparticle->GetFirstDaughter();
453 ipL = iparticle->GetLastDaughter();
454 if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
463 if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[i])
466 pc[0]=iparticle->Px();
467 pc[1]=iparticle->Py();
468 pc[2]=iparticle->Pz();
469 Bool_t childok = KinematicSelection(iparticle, 1);
480 } // if child selection
482 } // decay particle loop
483 } // if decay products
486 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
492 PushTrack(0, -1, iPart, p, origin0, polar, time0, kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
500 for (i = 1; i < np; i++) {
502 TParticle* iparticle = (TParticle *) particles->At(i);
503 Int_t kf = iparticle->GetPdgCode();
504 Int_t ksc = iparticle->GetStatusCode();
505 Int_t jpa = iparticle->GetFirstMother()-1;
507 och[0] = origin0[0]+iparticle->Vx();
508 och[1] = origin0[1]+iparticle->Vy();
509 och[2] = origin0[2]+iparticle->Vz();
510 pc[0] = iparticle->Px();
511 pc[1] = iparticle->Py();
512 pc[2] = iparticle->Pz();
515 iparent = pParent[jpa];
520 PushTrack(fTrackIt * trackIt[i], iparent, kf,
522 time0 + iparticle->T(), kPDecay, nt, wgtch, ksc);
530 if (pFlag) delete[] pFlag;
531 if (pParent) delete[] pParent;
532 if (pSelected) delete[] pSelected;
533 if (trackIt) delete[] trackIt;
534 } // kinematic selection
535 else // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
538 PushTrack(fTrackIt,-1,iPart,p,origin0,polar,time0,kPPrimary,nt,wgtp, 1);
546 SetHighWaterMark(nt);
548 AliGenEventHeader* header = new AliGenEventHeader("PARAM");
549 header->SetPrimaryVertex(fVertex);
550 header->SetInteractionTime(fTime);
551 header->SetNProduced(fNprimaries);
554 //____________________________________________________________________________________
555 Float_t AliGenParam::GetRelativeArea(Float_t ptMin, Float_t ptMax, Float_t yMin, Float_t yMax, Float_t phiMin, Float_t phiMax)
558 // Normalisation for selected kinematic region
561 fPtPara->Integral(ptMin,ptMax,(Double_t *)0,1.e-6) / fPtPara->Integral( fPtPara->GetXmin(), fPtPara->GetXmax(),(Double_t *)0,1.e-6) *
562 fYPara->Integral(yMin,yMax,(Double_t *)0,1.e-6)/fYPara->Integral(fYPara->GetXmin(),fYPara->GetXmax(),(Double_t *)0,1.e-6) *
563 (phiMax-phiMin)/360.;
564 return TMath::Abs(ratio);
567 //____________________________________________________________________________________
569 void AliGenParam::Draw( const char * /*opt*/)
572 // Draw the pT and y Distributions
574 TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
578 fPtPara->GetHistogram()->SetXTitle("p_{T} (GeV)");
581 fYPara->GetHistogram()->SetXTitle("y");