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 // Base class for generators using external MC generators.
19 // For example AliGenPythia using Pythia.
20 // Provides basic functionality: setting of kinematic cuts on
21 // decay products and particle selection.
22 // andreas.morsch@cern.ch
24 #include <TClonesArray.h>
27 #include <TParticle.h>
30 #include "AliGeometry.h"
37 // Default Constructor
39 SetChildMomentumRange();
45 SetGeometryAcceptance();
46 SetPdgCodeParticleforAcceptanceCut();
47 SetNumberOfAcceptedParticles();
55 AliGenMC::AliGenMC(Int_t npart)
60 SetChildMomentumRange();
68 for (Int_t i=0; i<8; i++) fParentSelect[i]=fChildSelect[i]=0;
70 SetGeometryAcceptance();
71 SetPdgCodeParticleforAcceptanceCut();
72 SetNumberOfAcceptedParticles();
78 AliGenMC::AliGenMC(const AliGenMC & mc):
94 switch (fForceDecay) {
97 case kBJpsiDiElectron:
98 case kBPsiPrimeDiElectron:
99 fChildSelect[0] = kElectron;
105 case kBPsiPrimeDiMuon:
108 fChildSelect[0]=kMuonMinus;
111 fChildSelect[0]=kPiPlus;
112 fChildSelect[1]=kKPlus;
115 fChildSelect[0]=kKPlus;
127 if (fZTarget != 0 && fAProjectile != 0)
129 fDyBoost = - 0.5 * TMath::Log(Double_t(fZProjectile) * Double_t(fATarget) /
130 (Double_t(fZTarget) * Double_t(fAProjectile)));
135 Bool_t AliGenMC::ParentSelected(Int_t ip) const
137 // True if particle is in list of parent particles to be selected
138 for (Int_t i=0; i<8; i++)
140 if (fParentSelect.At(i) == ip) return kTRUE;
145 Bool_t AliGenMC::ChildSelected(Int_t ip) const
147 // True if particle is in list of decay products to be selected
148 for (Int_t i=0; i<5; i++)
150 if (fChildSelect.At(i) == ip) return kTRUE;
155 Bool_t AliGenMC::KinematicSelection(TParticle *particle, Int_t flag) const
157 // Perform kinematic selection
158 Float_t pz = particle->Pz();
159 Float_t e = particle->Energy();
160 Float_t pt = particle->Pt();
161 Float_t p = particle->P();
162 Float_t theta = particle->Theta();
163 Float_t mass = particle->GetCalcMass();
164 Float_t mt2 = pt * pt + mass * mass;
165 Float_t phi = particle->Phi();
169 if (TMath::Abs(pz) < e) {
170 y = 0.5*TMath::Log((e+pz)/(e-pz));
176 y0 = 0.5*TMath::Log((e+TMath::Abs(pz))*(e+TMath::Abs(pz))/mt2);
178 if (TMath::Abs(y) < 1.e10) {
185 y = (pz < 0) ? -y0 : y0;
189 // Primary particle cuts
191 // transverse momentum cut
192 if (pt > fPtMax || pt < fPtMin) {
193 // printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
198 if (p > fPMax || p < fPMin) {
199 // printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
204 if (theta > fThetaMax || theta < fThetaMin) {
205 // printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
210 if (y > fYMax || y < fYMin) {
211 // printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
216 if (phi > fPhiMax || phi < fPhiMin) {
217 // printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
222 // Decay product cuts
224 // transverse momentum cut
225 if (pt > fChildPtMax || pt < fChildPtMin) {
226 // printf("\n failed pt cut %f %f %f \n",pt,fChildPtMin,fChildPtMax);
231 if (p > fChildPMax || p < fChildPMin) {
232 // printf("\n failed p cut %f %f %f \n",p,fChildPMin,fChildPMax);
237 if (theta > fChildThetaMax || theta < fChildThetaMin) {
238 // printf("\n failed theta cut %f %f %f \n",theta,fChildThetaMin,fChildThetaMax);
243 if (y > fChildYMax || y < fChildYMin) {
244 // printf("\n failed y cut %f %f %f \n",y,fChildYMin,fChildYMax);
249 if (phi > fChildPhiMax || phi < fChildPhiMin) {
250 // printf("\n failed phi cut %f %f %f \n",phi,fChildPhiMin,fChildPhiMax);
258 Bool_t AliGenMC::CheckAcceptanceGeometry(Int_t np, TClonesArray* particles)
260 // Check the geometrical acceptance for particle.
263 Int_t numberOfPdgCodeParticleforAcceptanceCut = 0;
264 Int_t numberOfAcceptedPdgCodeParticleforAcceptanceCut = 0;
265 TParticle * particle;
267 for (i = 0; i < np; i++) {
268 particle = (TParticle *) particles->At(i);
269 if( TMath::Abs( particle->GetPdgCode() ) == TMath::Abs( fPdgCodeParticleforAcceptanceCut ) ) {
270 numberOfPdgCodeParticleforAcceptanceCut++;
271 if (fGeometryAcceptance->Impact(particle)) numberOfAcceptedPdgCodeParticleforAcceptanceCut++;
274 if ( numberOfAcceptedPdgCodeParticleforAcceptanceCut > (fNumberOfAcceptedParticles-1) )
282 Int_t AliGenMC::CheckPDGCode(Int_t pdgcode) const
285 // If the particle is in a diffractive state, then take action accordingly
290 //rho_diff0 -- difficult to translate, return rho0
293 //pi_diffr+ -- change to pi+
296 //omega_di0 -- change to omega0
299 //phi_diff0 -- return phi0
302 //J/psi_di0 -- return J/psi
305 //n_diffr -- return neutron
308 //p_diffr+ -- return proton
311 //non diffractive state -- return code unchanged
315 void AliGenMC::Boost()
318 // Boost cms into LHC lab frame
321 Double_t beta = TMath::TanH(fDyBoost);
322 Double_t gamma = 1./TMath::Sqrt(1.-beta*beta);
323 Double_t gb = gamma * beta;
325 // printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);
328 Int_t np = fParticles->GetEntriesFast();
329 for (i = 0; i < np; i++)
331 TParticle* iparticle = (TParticle*) fParticles->At(i);
333 Double_t e = iparticle->Energy();
334 Double_t px = iparticle->Px();
335 Double_t py = iparticle->Py();
336 Double_t pz = iparticle->Pz();
338 Double_t eb = gamma * e - gb * pz;
339 Double_t pzb = -gb * e + gamma * pz;
341 iparticle->SetMomentum(px, py, pzb, eb);
347 AliGenMC& AliGenMC::operator=(const AliGenMC& rhs)
349 // Assignment operator
354 void AliGenMC::Copy(TObject&) const
359 Fatal("Copy","Not implemented!\n");