[u/mrichter/AliRoot.git] / EVGEN / AliGenMC.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

// Base class for generators using external MC generators.
// For example AliGenPythia using Pythia.
// Provides basic functionality: setting of kinematic cuts on 
// decay products and particle selection.
// andreas.morsch@cern.ch

#include <TClonesArray.h>
#include <TMath.h>
#include <TPDGCode.h>
#include <TParticle.h>

#include "AliGenMC.h"
#include "AliRun.h"
#include "AliGeometry.h"

ClassImp(AliGenMC)

AliGenMC::AliGenMC()
    :AliGenerator(),
     fParticles(0),
     fParentSelect(8),
     fChildSelect(8),
     fCutOnChild(0),
     fChildPtMin(0.),
     fChildPtMax(1.e10),
     fChildPMin(0.),
     fChildPMax(1.e10),
     fChildPhiMin(0.),
     fChildPhiMax(2. * TMath::Pi()),
     fChildThetaMin(0.),
     fChildThetaMax(TMath::Pi()),
     fChildYMin(-12.),
     fChildYMax(12.),
     fXingAngleX(0.),
     fXingAngleY(0.),
     fForceDecay(kAll),
     fMaxLifeTime(1.e-15),
     fAProjectile(1),
     fZProjectile(1),
     fATarget(1),
     fZTarget(1),
     fProjectile("P"),
     fTarget("P"),    
     fDyBoost(0.),
     fGeometryAcceptance(0),
     fPdgCodeParticleforAcceptanceCut(0),
     fNumberOfAcceptedParticles(0),
     fNprimaries(0)
{
// Default Constructor
}

AliGenMC::AliGenMC(Int_t npart)
    :AliGenerator(npart),
     fParticles(0),
     fParentSelect(8),
     fChildSelect(8),
     fCutOnChild(0),
     fChildPtMin(0.),
     fChildPtMax(1.e10),
     fChildPMin(0.),
     fChildPMax(1.e10),
     fChildPhiMin(0.),
     fChildPhiMax(2. * TMath::Pi()),
     fChildThetaMin(0.),
     fChildThetaMax(TMath::Pi()),
     fChildYMin(-12.),
     fChildYMax(12.),
     fXingAngleX(0.),
     fXingAngleY(0.),
     fForceDecay(kAll),
     fMaxLifeTime(1.e-15),
     fAProjectile(1),
     fZProjectile(1),
     fATarget(1),
     fZTarget(1),
     fProjectile("P"),
     fTarget("P"),    
     fDyBoost(0.),
     fGeometryAcceptance(0),
     fPdgCodeParticleforAcceptanceCut(0),
     fNumberOfAcceptedParticles(0),
     fNprimaries(0)
{
//  Constructor
// 
    for (Int_t i=0; i<8; i++) fParentSelect[i]=fChildSelect[i]=0;
}

AliGenMC::~AliGenMC()
{
// Destructor
}

void AliGenMC::Init()
{
//
//  Initialization
    switch (fForceDecay) {
    case kBSemiElectronic:
    case kSemiElectronic:
    case kDiElectron:
    case kBJpsiDiElectron:
    case kBPsiPrimeDiElectron:
	fChildSelect[0] = kElectron;	
	break;
    case kHardMuons:	
    case kBSemiMuonic:
    case kSemiMuonic:
    case kDiMuon:
    case kBJpsiDiMuon:
    case kBPsiPrimeDiMuon:
    case kPiToMu:
    case kKaToMu:
    case kWToMuon:
    case kWToCharmToMuon:
    case kZDiMuon:
    case kZDiElectron:
	fChildSelect[0]=kMuonMinus;
	break;
    case kWToCharm:
	break;
    case kHadronicD:
    case kHadronicDWithout4Bodies:
	fChildSelect[0]=kPiPlus;
	fChildSelect[1]=kKPlus;
	break;
    case kPhiKK:
	fChildSelect[0]=kKPlus;
	break;
    case kBJpsi:
	fChildSelect[0]= 443;
	break;
   case kChiToJpsiGammaToMuonMuon:
        fChildSelect[0]= 22;
        fChildSelect[1]= 13;
        break;
    case kChiToJpsiGammaToElectronElectron:
        fChildSelect[0]= 22;
        fChildSelect[1]= 11;
        break;

    case kOmega:	
    case kAll:
    case kAllMuonic:
    case kNoDecay:
    case kNoDecayHeavy:
    case kNeutralPion:
	break;
    }

    if (fZTarget != 0 && fAProjectile != 0) 
    {
	fDyBoost    = - 0.5 * TMath::Log(Double_t(fZProjectile) * Double_t(fATarget) / 
					 (Double_t(fZTarget)    * Double_t(fAProjectile)));
    }
}


Bool_t AliGenMC::ParentSelected(Int_t ip) const
{
// True if particle is in list of parent particles to be selected
    for (Int_t i=0; i<8; i++)
    {
	if (fParentSelect.At(i) == ip) return kTRUE;
    }
    return kFALSE;
}

Bool_t AliGenMC::ChildSelected(Int_t ip) const
{
// True if particle is in list of decay products to be selected
    for (Int_t i=0; i<5; i++)
    {
	if (fChildSelect.At(i) == ip) return kTRUE;
    }
    return kFALSE;
}

Bool_t AliGenMC::KinematicSelection(TParticle *particle, Int_t flag) const
{
// Perform kinematic selection
    Double_t pz    = particle->Pz();
    Double_t  e    = particle->Energy();
    Double_t pt    = particle->Pt();
    Double_t p     = particle->P();
    Double_t theta = particle->Theta();
    Double_t mass  = particle->GetCalcMass();
    Double_t mt2   = pt * pt + mass * mass;
    Double_t phi   = particle->Phi();
    
    Double_t y, y0;

    if (TMath::Abs(pz) <  e) {
	y = 0.5*TMath::Log((e+pz)/(e-pz));
    } else {
	y = 1.e10;
    }
    
    if (mt2) {
	y0 = 0.5*TMath::Log((e+TMath::Abs(pz))*(e+TMath::Abs(pz))/mt2);
    } else {
	if (TMath::Abs(y) < 1.e10) {
	    y0 = y;
	} else {
	    y0 = 1.e10;
	}
    }
      
    y = (pz < 0) ? -y0 : y0;
    
    if (flag == 0) {
//
// Primary particle cuts
//
//  transverse momentum cut    
	if (pt > fPtMax || pt < fPtMin) {
//	    printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
	    return kFALSE;
	}
//
// momentum cut
	if (p > fPMax || p < fPMin) {
//	    printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
	    return kFALSE;
	}
//
// theta cut
	if (theta > fThetaMax || theta < fThetaMin) {
//	    printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
	    return kFALSE;
	}
//
// rapidity cut
	if (y > fYMax || y < fYMin) {
//	    printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
	    return kFALSE;
	}
//
// phi cut
	if (phi > fPhiMax || phi < fPhiMin) {
//	    printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
	    return kFALSE;
	}
    } else {
//
// Decay product cuts
//
//  transverse momentum cut    
	if (pt > fChildPtMax || pt < fChildPtMin) {
//	    printf("\n failed pt cut %f %f %f \n",pt,fChildPtMin,fChildPtMax);
	    return kFALSE;
	}
//
// momentum cut
	if (p > fChildPMax || p < fChildPMin) {
//	    printf("\n failed p cut %f %f %f \n",p,fChildPMin,fChildPMax);
	    return kFALSE;
	}
//
// theta cut
	if (theta > fChildThetaMax || theta < fChildThetaMin) {
//	    printf("\n failed theta cut %f %f %f \n",theta,fChildThetaMin,fChildThetaMax);
	    return kFALSE;
	}
//
// rapidity cut
	if (y > fChildYMax || y < fChildYMin) {
//	    printf("\n failed y cut %f %f %f \n",y,fChildYMin,fChildYMax);
	    return kFALSE;
	}
//
// phi cut
	if (phi > fChildPhiMax || phi < fChildPhiMin) {
//	    printf("\n failed phi cut %f %f %f \n",phi,fChildPhiMin,fChildPhiMax);
	    return kFALSE;
	}
    }
    
    return kTRUE;
}

Bool_t AliGenMC::CheckAcceptanceGeometry(Int_t np, TClonesArray* particles)
{
// Check the geometrical acceptance for particle.

  Bool_t check ;  
  Int_t numberOfPdgCodeParticleforAcceptanceCut = 0;
  Int_t numberOfAcceptedPdgCodeParticleforAcceptanceCut = 0;
  TParticle * particle;
  Int_t i;
  for (i = 0; i < np; i++) {
    particle =  (TParticle *) particles->At(i);
    if( TMath::Abs( particle->GetPdgCode() ) == TMath::Abs( fPdgCodeParticleforAcceptanceCut ) ) {
      numberOfPdgCodeParticleforAcceptanceCut++;
      if (fGeometryAcceptance->Impact(particle)) numberOfAcceptedPdgCodeParticleforAcceptanceCut++;
    }   
  }
  if ( numberOfAcceptedPdgCodeParticleforAcceptanceCut > (fNumberOfAcceptedParticles-1) )
    check = kTRUE;
  else
    check = kFALSE;

  return check;
}

Int_t AliGenMC::CheckPDGCode(Int_t pdgcode) const
{
//
//  If the particle is in a diffractive state, then take action accordingly
  switch (pdgcode) {
  case 91:
    return 92;
  case 110:
    //rho_diff0 -- difficult to translate, return rho0
    return 113;
  case 210:
    //pi_diffr+ -- change to pi+
    return 211;
  case 220:
    //omega_di0 -- change to omega0
    return 223;
  case 330:
    //phi_diff0 -- return phi0
    return 333;
  case 440:
    //J/psi_di0 -- return J/psi
    return 443;
  case 2110:
    //n_diffr -- return neutron
    return 2112;
  case 2210:
    //p_diffr+ -- return proton
    return 2212;
  }
  //non diffractive state -- return code unchanged
  return pdgcode;
}

void AliGenMC::Boost()
{
//
// Boost cms into LHC lab frame
//

    Double_t beta  = TMath::TanH(fDyBoost);
    Double_t gamma = 1./TMath::Sqrt(1.-beta*beta);
    Double_t gb    = gamma * beta;

    //    printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);
    
    Int_t i;
    Int_t np = fParticles->GetEntriesFast();
    for (i = 0; i < np; i++) 
    {
	TParticle* iparticle = (TParticle*) fParticles->At(i);

	Double_t e   = iparticle->Energy();
	Double_t px  = iparticle->Px();
	Double_t py  = iparticle->Py();
	Double_t pz  = iparticle->Pz();

	Double_t eb  = gamma * e -      gb * pz;
	Double_t pzb =   -gb * e +   gamma * pz;

	iparticle->SetMomentum(px, py, pzb, eb);
    }
}

void AliGenMC::AddHeader(AliGenEventHeader* header)
{
    // Passes header either to the container or to gAlice
    if (fContainer) {
	fContainer->AddHeader(header);
    } else {
	gAlice->SetGenEventHeader(header);	
    }
}
Commit	Line	Data
	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	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	**************************************************************************/
	15
	16	/* $Id$ */
	17
	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
	23
	24	#include <TClonesArray.h>
	25	#include <TMath.h>
	26	#include <TPDGCode.h>
	27	#include <TParticle.h>
	28
	29	#include "AliGenMC.h"
	30	#include "AliRun.h"
	31	#include "AliGeometry.h"
	32
	33	ClassImp(AliGenMC)
	34
	35	AliGenMC::AliGenMC()
	36	:AliGenerator(),
	37	fParticles(0),
	38	fParentSelect(8),
	39	fChildSelect(8),
	40	fCutOnChild(0),
	41	fChildPtMin(0.),
	42	fChildPtMax(1.e10),
	43	fChildPMin(0.),
	44	fChildPMax(1.e10),
	45	fChildPhiMin(0.),
	46	fChildPhiMax(2. * TMath::Pi()),
	47	fChildThetaMin(0.),
	48	fChildThetaMax(TMath::Pi()),
	49	fChildYMin(-12.),
	50	fChildYMax(12.),
	51	fXingAngleX(0.),
	52	fXingAngleY(0.),
	53	fForceDecay(kAll),
	54	fMaxLifeTime(1.e-15),
	55	fAProjectile(1),
	56	fZProjectile(1),
	57	fATarget(1),
	58	fZTarget(1),
	59	fProjectile("P"),
	60	fTarget("P"),
	61	fDyBoost(0.),
	62	fGeometryAcceptance(0),
	63	fPdgCodeParticleforAcceptanceCut(0),
	64	fNumberOfAcceptedParticles(0),
	65	fNprimaries(0)
	66	{
	67	// Default Constructor
	68	}
	69
	70	AliGenMC::AliGenMC(Int_t npart)
	71	:AliGenerator(npart),
	72	fParticles(0),
	73	fParentSelect(8),
	74	fChildSelect(8),
	75	fCutOnChild(0),
	76	fChildPtMin(0.),
	77	fChildPtMax(1.e10),
	78	fChildPMin(0.),
	79	fChildPMax(1.e10),
	80	fChildPhiMin(0.),
	81	fChildPhiMax(2. * TMath::Pi()),
	82	fChildThetaMin(0.),
	83	fChildThetaMax(TMath::Pi()),
	84	fChildYMin(-12.),
	85	fChildYMax(12.),
	86	fXingAngleX(0.),
	87	fXingAngleY(0.),
	88	fForceDecay(kAll),
	89	fMaxLifeTime(1.e-15),
	90	fAProjectile(1),
	91	fZProjectile(1),
	92	fATarget(1),
	93	fZTarget(1),
	94	fProjectile("P"),
	95	fTarget("P"),
	96	fDyBoost(0.),
	97	fGeometryAcceptance(0),
	98	fPdgCodeParticleforAcceptanceCut(0),
	99	fNumberOfAcceptedParticles(0),
	100	fNprimaries(0)
	101	{
	102	// Constructor
	103	//
	104	for (Int_t i=0; i<8; i++) fParentSelect[i]=fChildSelect[i]=0;
	105	}
	106
	107	AliGenMC::~AliGenMC()
	108	{
	109	// Destructor
	110	}
	111
	112	void AliGenMC::Init()
	113	{
	114	//
	115	// Initialization
	116	switch (fForceDecay) {
	117	case kBSemiElectronic:
	118	case kSemiElectronic:
	119	case kDiElectron:
	120	case kBJpsiDiElectron:
	121	case kBPsiPrimeDiElectron:
	122	fChildSelect[0] = kElectron;
	123	break;
	124	case kHardMuons:
	125	case kBSemiMuonic:
	126	case kSemiMuonic:
	127	case kDiMuon:
	128	case kBJpsiDiMuon:
	129	case kBPsiPrimeDiMuon:
	130	case kPiToMu:
	131	case kKaToMu:
	132	case kWToMuon:
	133	case kWToCharmToMuon:
	134	case kZDiMuon:
	135	case kZDiElectron:
	136	fChildSelect[0]=kMuonMinus;
	137	break;
	138	case kWToCharm:
	139	break;
	140	case kHadronicD:
	141	case kHadronicDWithout4Bodies:
	142	fChildSelect[0]=kPiPlus;
	143	fChildSelect[1]=kKPlus;
	144	break;
	145	case kPhiKK:
	146	fChildSelect[0]=kKPlus;
	147	break;
	148	case kBJpsi:
	149	fChildSelect[0]= 443;
	150	break;
	151	case kChiToJpsiGammaToMuonMuon:
	152	fChildSelect[0]= 22;
	153	fChildSelect[1]= 13;
	154	break;
	155	case kChiToJpsiGammaToElectronElectron:
	156	fChildSelect[0]= 22;
	157	fChildSelect[1]= 11;
	158	break;
	159
	160	case kOmega:
	161	case kAll:
	162	case kAllMuonic:
	163	case kNoDecay:
	164	case kNoDecayHeavy:
	165	case kNeutralPion:
	166	break;
	167	}
	168
	169	if (fZTarget != 0 && fAProjectile != 0)
	170	{
	171	fDyBoost = - 0.5 * TMath::Log(Double_t(fZProjectile) * Double_t(fATarget) /
	172	(Double_t(fZTarget) * Double_t(fAProjectile)));
	173	}
	174	}
	175
	176
	177	Bool_t AliGenMC::ParentSelected(Int_t ip) const
	178	{
	179	// True if particle is in list of parent particles to be selected
	180	for (Int_t i=0; i<8; i++)
	181	{
	182	if (fParentSelect.At(i) == ip) return kTRUE;
	183	}
	184	return kFALSE;
	185	}
	186
	187	Bool_t AliGenMC::ChildSelected(Int_t ip) const
	188	{
	189	// True if particle is in list of decay products to be selected
	190	for (Int_t i=0; i<5; i++)
	191	{
	192	if (fChildSelect.At(i) == ip) return kTRUE;
	193	}
	194	return kFALSE;
	195	}
	196
	197	Bool_t AliGenMC::KinematicSelection(TParticle *particle, Int_t flag) const
	198	{
	199	// Perform kinematic selection
	200	Double_t pz = particle->Pz();
	201	Double_t e = particle->Energy();
	202	Double_t pt = particle->Pt();
	203	Double_t p = particle->P();
	204	Double_t theta = particle->Theta();
	205	Double_t mass = particle->GetCalcMass();
	206	Double_t mt2 = pt * pt + mass * mass;
	207	Double_t phi = particle->Phi();
	208
	209	Double_t y, y0;
	210
	211	if (TMath::Abs(pz) < e) {
	212	y = 0.5*TMath::Log((e+pz)/(e-pz));
	213	} else {
	214	y = 1.e10;
	215	}
	216
	217	if (mt2) {
	218	y0 = 0.5TMath::Log((e+TMath::Abs(pz))(e+TMath::Abs(pz))/mt2);
	219	} else {
	220	if (TMath::Abs(y) < 1.e10) {
	221	y0 = y;
	222	} else {
	223	y0 = 1.e10;
	224	}
	225	}
	226
	227	y = (pz < 0) ? -y0 : y0;
	228
	229	if (flag == 0) {
	230	//
	231	// Primary particle cuts
	232	//
	233	// transverse momentum cut
	234	if (pt > fPtMax \|\| pt < fPtMin) {
	235	// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
	236	return kFALSE;
	237	}
	238	//
	239	// momentum cut
	240	if (p > fPMax \|\| p < fPMin) {
	241	// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
	242	return kFALSE;
	243	}
	244	//
	245	// theta cut
	246	if (theta > fThetaMax \|\| theta < fThetaMin) {
	247	// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
	248	return kFALSE;
	249	}
	250	//
	251	// rapidity cut
	252	if (y > fYMax \|\| y < fYMin) {
	253	// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
	254	return kFALSE;
	255	}
	256	//
	257	// phi cut
	258	if (phi > fPhiMax \|\| phi < fPhiMin) {
	259	// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
	260	return kFALSE;
	261	}
	262	} else {
	263	//
	264	// Decay product cuts
	265	//
	266	// transverse momentum cut
	267	if (pt > fChildPtMax \|\| pt < fChildPtMin) {
	268	// printf("\n failed pt cut %f %f %f \n",pt,fChildPtMin,fChildPtMax);
	269	return kFALSE;
	270	}
	271	//
	272	// momentum cut
	273	if (p > fChildPMax \|\| p < fChildPMin) {
	274	// printf("\n failed p cut %f %f %f \n",p,fChildPMin,fChildPMax);
	275	return kFALSE;
	276	}
	277	//
	278	// theta cut
	279	if (theta > fChildThetaMax \|\| theta < fChildThetaMin) {
	280	// printf("\n failed theta cut %f %f %f \n",theta,fChildThetaMin,fChildThetaMax);
	281	return kFALSE;
	282	}
	283	//
	284	// rapidity cut
	285	if (y > fChildYMax \|\| y < fChildYMin) {
	286	// printf("\n failed y cut %f %f %f \n",y,fChildYMin,fChildYMax);
	287	return kFALSE;
	288	}
	289	//
	290	// phi cut
	291	if (phi > fChildPhiMax \|\| phi < fChildPhiMin) {
	292	// printf("\n failed phi cut %f %f %f \n",phi,fChildPhiMin,fChildPhiMax);
	293	return kFALSE;
	294	}
	295	}
	296
	297	return kTRUE;
	298	}
	299
	300	Bool_t AliGenMC::CheckAcceptanceGeometry(Int_t np, TClonesArray* particles)
	301	{
	302	// Check the geometrical acceptance for particle.
	303
	304	Bool_t check ;
	305	Int_t numberOfPdgCodeParticleforAcceptanceCut = 0;
	306	Int_t numberOfAcceptedPdgCodeParticleforAcceptanceCut = 0;
	307	TParticle * particle;
	308	Int_t i;
	309	for (i = 0; i < np; i++) {
	310	particle = (TParticle *) particles->At(i);
	311	if( TMath::Abs( particle->GetPdgCode() ) == TMath::Abs( fPdgCodeParticleforAcceptanceCut ) ) {
	312	numberOfPdgCodeParticleforAcceptanceCut++;
	313	if (fGeometryAcceptance->Impact(particle)) numberOfAcceptedPdgCodeParticleforAcceptanceCut++;
	314	}
	315	}
	316	if ( numberOfAcceptedPdgCodeParticleforAcceptanceCut > (fNumberOfAcceptedParticles-1) )
	317	check = kTRUE;
	318	else
	319	check = kFALSE;
	320
	321	return check;
	322	}
	323
	324	Int_t AliGenMC::CheckPDGCode(Int_t pdgcode) const
	325	{
	326	//
	327	// If the particle is in a diffractive state, then take action accordingly
	328	switch (pdgcode) {
	329	case 91:
	330	return 92;
	331	case 110:
	332	//rho_diff0 -- difficult to translate, return rho0
	333	return 113;
	334	case 210:
	335	//pi_diffr+ -- change to pi+
	336	return 211;
	337	case 220:
	338	//omega_di0 -- change to omega0
	339	return 223;
	340	case 330:
	341	//phi_diff0 -- return phi0
	342	return 333;
	343	case 440:
	344	//J/psi_di0 -- return J/psi
	345	return 443;
	346	case 2110:
	347	//n_diffr -- return neutron
	348	return 2112;
	349	case 2210:
	350	//p_diffr+ -- return proton
	351	return 2212;
	352	}
	353	//non diffractive state -- return code unchanged
	354	return pdgcode;
	355	}
	356
	357	void AliGenMC::Boost()
	358	{
	359	//
	360	// Boost cms into LHC lab frame
	361	//
	362
	363	Double_t beta = TMath::TanH(fDyBoost);
	364	Double_t gamma = 1./TMath::Sqrt(1.-beta*beta);
	365	Double_t gb = gamma * beta;
	366
	367	// printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);
	368
	369	Int_t i;
	370	Int_t np = fParticles->GetEntriesFast();
	371	for (i = 0; i < np; i++)
	372	{
	373	TParticle* iparticle = (TParticle*) fParticles->At(i);
	374
	375	Double_t e = iparticle->Energy();
	376	Double_t px = iparticle->Px();
	377	Double_t py = iparticle->Py();
	378	Double_t pz = iparticle->Pz();
	379
	380	Double_t eb = gamma * e - gb * pz;
	381	Double_t pzb = -gb * e + gamma * pz;
	382
	383	iparticle->SetMomentum(px, py, pzb, eb);
	384	}
	385	}
	386
	387	void AliGenMC::AddHeader(AliGenEventHeader* header)
	388	{
	389	// Passes header either to the container or to gAlice
	390	if (fContainer) {
	391	fContainer->AddHeader(header);
	392	} else {
	393	gAlice->SetGenEventHeader(header);
	394	}
	395	}