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"
45 fChildPhiMax(2. * TMath::Pi()),
47 fChildThetaMax(TMath::Pi()),
61 fGeometryAcceptance(0),
62 fPdgCodeParticleforAcceptanceCut(0),
63 fNumberOfAcceptedParticles(2)
65 // Default Constructor
68 AliGenMC::AliGenMC(Int_t npart)
79 fChildPhiMax(2. * TMath::Pi()),
81 fChildThetaMax(TMath::Pi()),
95 fGeometryAcceptance(0),
96 fPdgCodeParticleforAcceptanceCut(0),
97 fNumberOfAcceptedParticles(2)
101 for (Int_t i=0; i<8; i++) fParentSelect[i]=fChildSelect[i]=0;
104 AliGenMC::~AliGenMC()
109 void AliGenMC::Init()
113 switch (fForceDecay) {
114 case kSemiElectronic:
116 case kBJpsiDiElectron:
117 case kBPsiPrimeDiElectron:
118 fChildSelect[0] = kElectron;
124 case kBPsiPrimeDiMuon:
128 case kWToCharmToMuon:
130 fChildSelect[0]=kMuonMinus;
135 fChildSelect[0]=kPiPlus;
136 fChildSelect[1]=kKPlus;
139 fChildSelect[0]=kKPlus;
151 if (fZTarget != 0 && fAProjectile != 0)
153 fDyBoost = - 0.5 * TMath::Log(Double_t(fZProjectile) * Double_t(fATarget) /
154 (Double_t(fZTarget) * Double_t(fAProjectile)));
159 Bool_t AliGenMC::ParentSelected(Int_t ip) const
161 // True if particle is in list of parent particles to be selected
162 for (Int_t i=0; i<8; i++)
164 if (fParentSelect.At(i) == ip) return kTRUE;
169 Bool_t AliGenMC::ChildSelected(Int_t ip) const
171 // True if particle is in list of decay products to be selected
172 for (Int_t i=0; i<5; i++)
174 if (fChildSelect.At(i) == ip) return kTRUE;
179 Bool_t AliGenMC::KinematicSelection(TParticle *particle, Int_t flag) const
181 // Perform kinematic selection
182 Float_t pz = particle->Pz();
183 Float_t e = particle->Energy();
184 Float_t pt = particle->Pt();
185 Float_t p = particle->P();
186 Float_t theta = particle->Theta();
187 Float_t mass = particle->GetCalcMass();
188 Float_t mt2 = pt * pt + mass * mass;
189 Float_t phi = particle->Phi();
193 if (TMath::Abs(pz) < e) {
194 y = 0.5*TMath::Log((e+pz)/(e-pz));
200 y0 = 0.5*TMath::Log((e+TMath::Abs(pz))*(e+TMath::Abs(pz))/mt2);
202 if (TMath::Abs(y) < 1.e10) {
209 y = (pz < 0) ? -y0 : y0;
213 // Primary particle cuts
215 // transverse momentum cut
216 if (pt > fPtMax || pt < fPtMin) {
217 // printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
222 if (p > fPMax || p < fPMin) {
223 // printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
228 if (theta > fThetaMax || theta < fThetaMin) {
229 // printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
234 if (y > fYMax || y < fYMin) {
235 // printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
240 if (phi > fPhiMax || phi < fPhiMin) {
241 // printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
246 // Decay product cuts
248 // transverse momentum cut
249 if (pt > fChildPtMax || pt < fChildPtMin) {
250 // printf("\n failed pt cut %f %f %f \n",pt,fChildPtMin,fChildPtMax);
255 if (p > fChildPMax || p < fChildPMin) {
256 // printf("\n failed p cut %f %f %f \n",p,fChildPMin,fChildPMax);
261 if (theta > fChildThetaMax || theta < fChildThetaMin) {
262 // printf("\n failed theta cut %f %f %f \n",theta,fChildThetaMin,fChildThetaMax);
267 if (y > fChildYMax || y < fChildYMin) {
268 // printf("\n failed y cut %f %f %f \n",y,fChildYMin,fChildYMax);
273 if (phi > fChildPhiMax || phi < fChildPhiMin) {
274 // printf("\n failed phi cut %f %f %f \n",phi,fChildPhiMin,fChildPhiMax);
282 Bool_t AliGenMC::CheckAcceptanceGeometry(Int_t np, TClonesArray* particles)
284 // Check the geometrical acceptance for particle.
287 Int_t numberOfPdgCodeParticleforAcceptanceCut = 0;
288 Int_t numberOfAcceptedPdgCodeParticleforAcceptanceCut = 0;
289 TParticle * particle;
291 for (i = 0; i < np; i++) {
292 particle = (TParticle *) particles->At(i);
293 if( TMath::Abs( particle->GetPdgCode() ) == TMath::Abs( fPdgCodeParticleforAcceptanceCut ) ) {
294 numberOfPdgCodeParticleforAcceptanceCut++;
295 if (fGeometryAcceptance->Impact(particle)) numberOfAcceptedPdgCodeParticleforAcceptanceCut++;
298 if ( numberOfAcceptedPdgCodeParticleforAcceptanceCut > (fNumberOfAcceptedParticles-1) )
306 Int_t AliGenMC::CheckPDGCode(Int_t pdgcode) const
309 // If the particle is in a diffractive state, then take action accordingly
314 //rho_diff0 -- difficult to translate, return rho0
317 //pi_diffr+ -- change to pi+
320 //omega_di0 -- change to omega0
323 //phi_diff0 -- return phi0
326 //J/psi_di0 -- return J/psi
329 //n_diffr -- return neutron
332 //p_diffr+ -- return proton
335 //non diffractive state -- return code unchanged
339 void AliGenMC::Boost()
342 // Boost cms into LHC lab frame
345 Double_t beta = TMath::TanH(fDyBoost);
346 Double_t gamma = 1./TMath::Sqrt(1.-beta*beta);
347 Double_t gb = gamma * beta;
349 // printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);
352 Int_t np = fParticles->GetEntriesFast();
353 for (i = 0; i < np; i++)
355 TParticle* iparticle = (TParticle*) fParticles->At(i);
357 Double_t e = iparticle->Energy();
358 Double_t px = iparticle->Px();
359 Double_t py = iparticle->Py();
360 Double_t pz = iparticle->Pz();
362 Double_t eb = gamma * e - gb * pz;
363 Double_t pzb = -gb * e + gamma * pz;
365 iparticle->SetMomentum(px, py, pzb, eb);