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AliGenParam.cxx
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AliGenParam.cxx
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/**************************************************************************
* 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. *
**************************************************************************/
/* $Id$ */
// Class to generate particles from using paramtrized pT and y distributions.
// Distributions are obtained from pointer to object of type AliGenLib.
// (For example AliGenMUONlib)
// Decays are performed using Pythia.
#include <TCanvas.h>
#include <TClonesArray.h>
#include <TDatabasePDG.h>
#include <TF1.h>
#include <TH1F.h>
#include <TLorentzVector.h>
#include <TMath.h>
#include <TParticle.h>
#include <TParticlePDG.h>
#include <TROOT.h>
#include <TVirtualMC.h>
#include "AliDecayer.h"
#include "AliGenMUONlib.h"
#include "AliGenParam.h"
#include "AliMC.h"
#include "AliRun.h"
#include "AliGenEventHeader.h"
ClassImp(AliGenParam)
//------------------------------------------------------------
//Begin_Html
/*
<img src="picts/AliGenParam.gif">
*/
//End_Html
//____________________________________________________________
AliGenParam::AliGenParam()
: fPtParaFunc(0),
fYParaFunc(0),
fIpParaFunc(0),
fV2ParaFunc(0),
fPtPara(0),
fYPara(0),
fV2Para(0),
fdNdPhi(0),
fParam(0),
fdNdy0(0.),
fYWgt(0.),
fPtWgt(0.),
fBias(0.),
fTrials(0),
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
fForceConv(kFALSE),
fKeepParent(kFALSE),
fKeepIfOneChildSelected(kFALSE),
fPreserveFullDecayChain(kFALSE),
fPDGcode(0),
fIncFortran(-1)
{
// Default constructor
}
//____________________________________________________________
AliGenParam::AliGenParam(Int_t npart, const AliGenLib * Library, Int_t param, const char* tname)
:AliGenMC(npart),
fPtParaFunc(Library->GetPt(param, tname)),
fYParaFunc (Library->GetY (param, tname)),
fIpParaFunc(Library->GetIp(param, tname)),
fV2ParaFunc(Library->GetV2(param, tname)),
fPtPara(0),
fYPara(0),
fV2Para(0),
fdNdPhi(0),
fParam(param),
fdNdy0(0.),
fYWgt(0.),
fPtWgt(0.),
fBias(0.),
fTrials(0),
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
fForceConv(kFALSE),
fKeepParent(kFALSE),
fKeepIfOneChildSelected(kFALSE),
fPreserveFullDecayChain(kFALSE),
fPDGcode(0),
fIncFortran(-1)
{
// Constructor using number of particles parameterisation id and library
fName = "Param";
fTitle = "Particle Generator using pT and y parameterisation";
fAnalog = kAnalog;
SetForceDecay();
}
//____________________________________________________________
AliGenParam::AliGenParam(Int_t npart, Int_t param, const char* tname, const char* name):
AliGenMC(npart),
fPtParaFunc(0),
fYParaFunc (0),
fIpParaFunc(0),
fV2ParaFunc(0),
fPtPara(0),
fYPara(0),
fV2Para(0),
fdNdPhi(0),
fParam(param),
fdNdy0(0.),
fYWgt(0.),
fPtWgt(0.),
fBias(0.),
fTrials(0),
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
fForceConv(kFALSE),
fKeepParent(kFALSE),
fKeepIfOneChildSelected(kFALSE),
fPreserveFullDecayChain(kFALSE),
fPDGcode(0),
fIncFortran(-1)
{
// Constructor using parameterisation id and number of particles
//
fName = name;
fTitle = "Particle Generator using pT and y parameterisation";
AliGenLib* pLibrary = new AliGenMUONlib();
fPtParaFunc = pLibrary->GetPt(param, tname);
fYParaFunc = pLibrary->GetY (param, tname);
fIpParaFunc = pLibrary->GetIp(param, tname);
fV2ParaFunc = pLibrary->GetV2(param, tname);
fAnalog = kAnalog;
fChildSelect.Set(5);
for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
SetForceDecay();
SetCutOnChild();
SetChildMomentumRange();
SetChildPtRange();
SetChildPhiRange();
SetChildThetaRange();
}
//____________________________________________________________
AliGenParam::AliGenParam(Int_t npart, Int_t param,
Double_t (*PtPara) (const Double_t*, const Double_t*),
Double_t (*YPara ) (const Double_t* ,const Double_t*),
Double_t (*V2Para) (const Double_t* ,const Double_t*),
Int_t (*IpPara) (TRandom *))
:AliGenMC(npart),
fPtParaFunc(PtPara),
fYParaFunc(YPara),
fIpParaFunc(IpPara),
fV2ParaFunc(V2Para),
fPtPara(0),
fYPara(0),
fV2Para(0),
fdNdPhi(0),
fParam(param),
fdNdy0(0.),
fYWgt(0.),
fPtWgt(0.),
fBias(0.),
fTrials(0),
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
fForceConv(kFALSE),
fKeepParent(kFALSE),
fKeepIfOneChildSelected(kFALSE),
fPDGcode(0),
fIncFortran(-1)
{
// Constructor
// Gines Martinez 1/10/99
fName = "Param";
fTitle = "Particle Generator using pT and y parameterisation";
fAnalog = kAnalog;
fChildSelect.Set(5);
for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
SetForceDecay();
SetCutOnChild();
SetChildMomentumRange();
SetChildPtRange();
SetChildPhiRange();
SetChildThetaRange();
}
//____________________________________________________________
AliGenParam::AliGenParam(const char* name, Int_t npart, int pdg,
Double_t (*PtPara) (const Double_t*, const Double_t*),
Double_t (*YPara ) (const Double_t* ,const Double_t*),
Double_t (*V2Para) (const Double_t* ,const Double_t*))
:AliGenMC(npart),
fPtParaFunc(0x0),
fYParaFunc(0x0),
fIpParaFunc(0x0),
fV2ParaFunc(0x0),
fPtPara(0),
fYPara(0),
fV2Para(0),
fdNdPhi(0),
fParam(0),
fdNdy0(0.),
fYWgt(0.),
fPtWgt(0.),
fBias(0.),
fTrials(0),
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
fForceConv(kFALSE),
fKeepParent(kFALSE),
fKeepIfOneChildSelected(kFALSE),
fPDGcode(pdg),
fIncFortran(-1)
{
// Constructor
// Gines Martinez 1/10/99
fName = name;
fTitle = Form("Particle Generator using pT and y parameterisation for %s",name);
fAnalog = kAnalog;
fChildSelect.Set(5);
for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
SetForceDecay();
SetCutOnChild();
SetChildMomentumRange();
SetChildPtRange();
SetChildPhiRange();
SetChildThetaRange();
fPtParaFunc = PtPara ? PtPara : [](const double*, const double*) -> double { return 1.; };
fYParaFunc = YPara ? YPara : [](const double*, const double*) -> double { return 1.; };
fV2ParaFunc = V2Para ? V2Para : [](const double*, const double*) -> double { return 0.; };
}
//____________________________________________________________
AliGenParam::~AliGenParam()
{
// Destructor
delete fPtPara;
delete fYPara;
delete fV2Para;
delete fdNdPhi;
}
//-------------------------------------------------------------------
TVector3 AliGenParam::OrthogonalVector(TVector3 &inVec){
double abc[]={inVec.x(), inVec.y(), inVec.z()};
double xyz[]={1,1,1};
int solvDim=0;
double tmp=abc[0];
for(int i=0; i<3; i++)
if(fabs(abc[i])>tmp){
solvDim=i;
tmp=fabs(abc[i]);
}
xyz[solvDim]=(-abc[(1+solvDim)%3]-abc[(2+solvDim)%3])/abc[(0+solvDim)%3];
TVector3 res(xyz[0],xyz[1],xyz[2]);
return res;
}
void AliGenParam::RotateVector(Double_t *pin, Double_t *pout, Double_t costheta, Double_t sintheta,
Double_t cosphi, Double_t sinphi)
{
// Perform rotation
pout[0] = pin[0]*costheta*cosphi-pin[1]*sinphi+pin[2]*sintheta*cosphi;
pout[1] = pin[0]*costheta*sinphi+pin[1]*cosphi+pin[2]*sintheta*sinphi;
pout[2] = -1.0 * pin[0] * sintheta + pin[2] * costheta;
return;
}
double AliGenParam::ScreenFunction1(double screenVariable){
if(screenVariable>1)
return 42.24 - 8.368 * log(screenVariable + 0.952);
else
return 42.392 - screenVariable * (7.796 - 1.961 * screenVariable);
}
double AliGenParam::ScreenFunction2(double screenVariable){
if(screenVariable>1)
return 42.24 - 8.368 * log(screenVariable + 0.952);
else
return 41.405 - screenVariable * (5.828 - 0.8945 * screenVariable);
}
double AliGenParam::RandomEnergyFraction(double Z, double photonEnergy){
double aZ=Z/137.036;
double epsilon ;
double epsilon0Local = 0.000511 / photonEnergy ;
// Do it fast if photon energy < 2. MeV
if (photonEnergy < 0.002 ){
epsilon = epsilon0Local + (0.5 - epsilon0Local) * fRandom->Rndm();
} else {
double fZ = 8*log(Z)/3;
double fcZ=(aZ*aZ)*(1/(1+aZ*aZ)+0.20206-0.0368*aZ*aZ+0.0083*aZ*aZ*aZ);
if (photonEnergy > 0.050) fZ += 8*fcZ;
// Limits of the screening variable
double screenFactor = 136. * epsilon0Local / pow (Z,1/3);
double screenMax = exp ((42.24 - fZ)/8.368) - 0.952 ;
double screenMin = std::min(4.*screenFactor,screenMax) ;
// Limits of the energy sampling
double epsilon1 = 0.5 - 0.5 * sqrt(1. - screenMin / screenMax) ;
double epsilonMin = std::max(epsilon0Local,epsilon1);
double epsilonRange = 0.5 - epsilonMin ;
// Sample the energy rate of the created electron (or positron)
double screen;
double gReject ;
double f10 = ScreenFunction1(screenMin) - fZ;
double f20 = ScreenFunction2(screenMin) - fZ;
double normF1 = std::max(f10 * epsilonRange * epsilonRange,0.);
double normF2 = std::max(1.5 * f20,0.);
do {
if (normF1 / (normF1 + normF2) > fRandom->Rndm() ){
epsilon = 0.5 - epsilonRange * pow(fRandom->Rndm(), 0.333333) ;
screen = screenFactor / (epsilon * (1. - epsilon));
gReject = (ScreenFunction1(screen) - fZ) / f10 ;
} else {
epsilon = epsilonMin + epsilonRange * fRandom->Rndm();
screen = screenFactor / (epsilon * (1 - epsilon));
gReject = (ScreenFunction2(screen) - fZ) / f20 ;
}
} while ( gReject < fRandom->Rndm() );
} // End of epsilon sampling
return epsilon;
}
double AliGenParam::RandomPolarAngle(){
double u;
const double a1 = 0.625;
double a2 = 3. * a1;
// double d = 27. ;
// if (9. / (9. + d) > fRandom->Rndm())
if (0.25 > fRandom->Rndm()) {
u = - log(fRandom->Rndm() * fRandom->Rndm()) / a1 ;
} else {
u = - log(fRandom->Rndm() * fRandom->Rndm()) / a2 ;
}
return u*0.000511;
}
Double_t AliGenParam::RandomMass(Double_t mh){
while(true){
double y=fRandom->Rndm();
double mee=2*0.000511*TMath::Power(2*0.000511/mh,-y); //inverse of the enveloping cumulative distribution
double apxkw=2.0/3.0/137.036/TMath::Pi()/mee; //enveloping probability density
double val=fRandom->Uniform(0,apxkw);
double kw=apxkw*sqrt(1-4*0.000511*0.000511/mee/mee)*(1+2*0.000511*0.000511/mee/mee)*1*1*TMath::Power(1-mee*mee/mh/mh,3);
if(val<kw)
return mee;
}
}
Int_t AliGenParam::VirtualGammaPairProduction(TClonesArray *particles, Int_t nPart)
{
Int_t nPartNew=nPart;
for(int iPart=0; iPart<nPart; iPart++){
TParticle *gamma = (TParticle *) particles->At(iPart);
if(gamma->GetPdgCode()!=220001) continue;
if(gamma->Pt()<0.002941) continue; //approximation of kw in AliGenEMlib is 0 below 0.002941
double mass=RandomMass(gamma->Pt());
// lepton pair kinematics in virtual photon rest frame
double Ee=mass/2;
double Pe=TMath::Sqrt((Ee+0.000511)*(Ee-0.000511));
double costheta = (2.0 * gRandom->Rndm()) - 1.;
double sintheta = TMath::Sqrt((1. + costheta) * (1. - costheta));
double phi = 2.0 * TMath::ACos(-1.) * gRandom->Rndm();
double sinphi = TMath::Sin(phi);
double cosphi = TMath::Cos(phi);
// momentum vectors of leptons in virtual photon rest frame
Double_t pProd1[3] = {Pe * sintheta * cosphi,
Pe * sintheta * sinphi,
Pe * costheta};
Double_t pProd2[3] = {-1.0 * Pe * sintheta * cosphi,
-1.0 * Pe * sintheta * sinphi,
-1.0 * Pe * costheta};
// lepton 4-vectors in properly rotated virtual photon rest frame
Double_t pRot1[3] = {0.};
RotateVector(pProd1, pRot1, costheta, -sintheta, -cosphi, -sinphi);
Double_t pRot2[3] = {0.};
RotateVector(pProd2, pRot2, costheta, -sintheta, -cosphi, -sinphi);
TLorentzVector e1V4(pRot1[0],pRot1[1],pRot1[2],Ee);
TLorentzVector e2V4(pRot2[0],pRot2[1],pRot2[2],Ee);
TVector3 boost(gamma->Px(),gamma->Py(),gamma->Pz());
boost*=1/sqrt(gamma->P()*gamma->P()+mass*mass);
e1V4.Boost(boost);
e2V4.Boost(boost);
TLorentzVector vtx;
gamma->ProductionVertex(vtx);
new((*particles)[nPartNew]) TParticle(11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, e1V4, vtx);
nPartNew++;
new((*particles)[nPartNew]) TParticle(-11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, e2V4, vtx);
nPartNew++;
}
return nPartNew;
}
Int_t AliGenParam::ForceGammaConversion(TClonesArray *particles, Int_t nPart)
{
//based on: http://geant4.cern.ch/G4UsersDocuments/UsersGuides/PhysicsReferenceManual/html/node27.html
// and: http://geant4.cern.ch/G4UsersDocuments/UsersGuides/PhysicsReferenceManual/html/node58.html
// and: G4LivermoreGammaConversionModel.cc
Int_t nPartNew=nPart;
for(int iPart=0; iPart<nPart; iPart++){
TParticle *gamma = (TParticle *) particles->At(iPart);
if(gamma->GetPdgCode()!=22 & gamma->GetPdgCode()!=220000) continue;
if(gamma->Energy()<=0.001022) continue;
TVector3 gammaV3(gamma->Px(),gamma->Py(),gamma->Pz());
double frac=RandomEnergyFraction(1,gamma->Energy());
double Ee1=frac*gamma->Energy();
double Ee2=(1-frac)*gamma->Energy();
double Pe1=sqrt((Ee1+0.000511)*(Ee1-0.000511));
double Pe2=sqrt((Ee2+0.000511)*(Ee2-0.000511));
TVector3 rotAxis(OrthogonalVector(gammaV3));
Float_t az=fRandom->Uniform(TMath::Pi()*2);
rotAxis.Rotate(az,gammaV3);
TVector3 e1V3(gammaV3);
double u=RandomPolarAngle();
e1V3.Rotate(u/Ee1,rotAxis);
e1V3=e1V3.Unit();
e1V3*=Pe1;
TVector3 e2V3(gammaV3);
e2V3.Rotate(-u/Ee2,rotAxis);
e2V3=e2V3.Unit();
e2V3*=Pe2;
// gamma = new TParticle(*gamma);
// particles->RemoveAt(iPart);
gamma->SetFirstDaughter(nPartNew+1);
gamma->SetLastDaughter(nPartNew+2);
// new((*particles)[iPart]) TParticle(*gamma);
// delete gamma;
// conversion probability per atom
// fitted G4EMLOW6.35/pair/pp-cs-8.dat, fit is great for E>20MeV
double convProb = 1/(exp(-log(28.44*(gamma->Energy()-0.001022))*(0.775+0.0271*log(gamma->Energy()+1)))+1);
// radiation length is not considered here, so you have to normalize yourself in after-production from infinite radiation length to whatever you want
// double meanExessPathlength=0.5*(exp(0.9)-exp(-0.9))/0.9; double scale=(1-exp(-7.0/9.0*radLength*meanExessPathlength))/(1-0);
TLorentzVector vtx;
gamma->ProductionVertex(vtx);
TParticle *currPart;
Int_t sign = (gRandom->Rndm() < 0.5) ? 1 : -1;
currPart = new((*particles)[nPartNew]) TParticle(sign * 220011, gamma->GetStatusCode(), iPart+1, -1, 0, 0, TLorentzVector(e1V3,Ee1), vtx);
currPart->SetWeight(convProb);
nPartNew++;
currPart = new((*particles)[nPartNew]) TParticle(- sign * 220011, gamma->GetStatusCode(), iPart+1, -1, 0, 0, TLorentzVector(e2V3,Ee2), vtx);
currPart->SetWeight(convProb);
nPartNew++;
}
return nPartNew;
}
//____________________________________________________________
void AliGenParam::Init()
{
// Initialisation
if (!fDecayer && TVirtualMC::GetMC()) fDecayer = TVirtualMC::GetMC()->GetDecayer();
if (!fDecayer){
Fatal("AliGenParam",
"No decayer attached");
}
// For AliDecayerPythia based on FORTRAN there is a known inconsitency between the index returned by
// GetFirstDaughter(), GetLastDaughter(), GetMother() ... and the actual position in the C++ particle list.
// That's the reason whe the offset fIncFortran = -1 is needed in this case but not for decayers based on
// C++
if (strcmp(fDecayer->ClassName(), "AliDecayerPythia")) fIncFortran = 0;
//Begin_Html
/*
<img src="picts/AliGenParam.gif">
*/
//End_Html
char name[256];
snprintf(name, 256, "pt-parameterisation for %s", GetName());
if (fPtPara) fPtPara->Delete();
fPtPara = new TF1(name, fPtParaFunc, fPtMin, fPtMax,0);
gROOT->GetListOfFunctions()->Remove(fPtPara);
// Set representation precision to 10 MeV
Int_t npx= Int_t((fPtMax - fPtMin) / fDeltaPt);
fPtPara->SetNpx(npx);
snprintf(name, 256, "y-parameterisation for %s", GetName());
if (fYPara) fYPara->Delete();
fYPara = new TF1(name, fYParaFunc, fYMin, fYMax, 0);
gROOT->GetListOfFunctions()->Remove(fYPara);
snprintf(name, 256, "v2-parameterisation for %s", GetName());
if (fV2Para) fV2Para->Delete();
fV2Para = new TF1(name, fV2ParaFunc, fPtMin, fPtMax, 0);
// fV2Para = new TF1(name, "2*[0]/(1+TMath::Exp([1]*([2]-x)))-[0]", fPtMin, fPtMax);
// fV2Para->SetParameter(0, 0.236910);
// fV2Para->SetParameter(1, 1.71122);
// fV2Para->SetParameter(2, 0.0827617);
//gROOT->GetListOfFunctions()->Remove(fV2Para); //TR: necessary?
snprintf(name, 256, "dNdPhi for %s", GetName());
if (fdNdPhi) fdNdPhi->Delete();
fdNdPhi = new TF1(name, "1+2*[0]*TMath::Cos(2*(x-[1]))", fPhiMin, fPhiMax);
//gROOT->GetListOfFunctions()->Remove(fdNdPhi); //TR: necessary?
snprintf(name, 256, "pt-for-%s", GetName());
TF1 ptPara(name ,fPtParaFunc, 0, 15, 0);
snprintf(name, 256, "y-for-%s", GetName());
TF1 yPara(name, fYParaFunc, -6, 6, 0);
//
// dN/dy| y=0
Double_t y1=0;
Double_t y2=0;
fdNdy0=fYParaFunc(&y1,&y2);
//
// Integral over generation region
#if ROOT_VERSION_CODE < ROOT_VERSION(5,99,0)
Float_t intYS = yPara.Integral(fYMin, fYMax,(Double_t*) 0x0,1.e-6);
Float_t intPt0 = ptPara.Integral(0,15,(Double_t *) 0x0,1.e-6);
Float_t intPtS = ptPara.Integral(fPtMin,fPtMax,(Double_t*) 0x0,1.e-6);
#else
Float_t intYS = yPara.Integral(fYMin, fYMax,1.e-6);
Float_t intPt0 = ptPara.Integral(0,15,1.e-6);
Float_t intPtS = ptPara.Integral(fPtMin,fPtMax,1.e-6);
#endif
Float_t phiWgt=(fPhiMax-fPhiMin)/TMath::TwoPi(); //TR: should probably be done differently in case of anisotropic phi...
if (fAnalog == kAnalog) {
fYWgt = intYS/fdNdy0;
fPtWgt = intPtS/intPt0;
fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
} else {
fYWgt = intYS/fdNdy0;
fPtWgt = (fPtMax-fPtMin)/intPt0;
fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
}
//
// particle decay related initialization
fDecayer->SetForceDecay(fForceDecay);
fDecayer->Init();
//
AliGenMC::Init();
}
//____________________________________________________________
void AliGenParam::Generate()
{
//
// Generate 1 event (see Generate(Int_t ntimes) for details
//
GenerateN(1);
}
//____________________________________________________________
void AliGenParam::GenerateN(Int_t ntimes)
{
//
// Generate ntimes*'npart' light and heavy mesons (J/Psi, upsilon or phi, Pion,
// Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and
// antineutrons in the the desired theta, phi and momentum windows;
// Gaussian smearing on the vertex is done if selected.
// The decay of heavy mesons is done using lujet,
// and the childern particle are tracked by GEANT
// However, light mesons are directly tracked by GEANT
// setting fForceDecay = nodecay (SetForceDecay(nodecay))
//
//
// Reinitialize decayer
fDecayer->SetForceDecay(fForceDecay);
fDecayer->Init();
//
Float_t polar[3]= {0,0,0}; // Polarisation of the parent particle (for GEANT tracking)
Double_t origin0[3]; // Origin of the generated parent particle (for GEANT tracking)
Double_t time0; // Time0 of the generated parent particle
Double_t pt, pl, ptot; // Transverse, logitudinal and total momenta of the parent particle
Double_t phi, theta; // Phi and theta spherical angles of the parent particle momentum
Double_t p[3], pc[3], och[3];// Momentum, polarisation and origin of the children particles from lujet
Double_t ty, xmt;
Int_t nt, i, j;
Double_t energy;
Float_t wgtp, wgtch;
Double_t dummy;
static TClonesArray *particles;
//
if(!particles) particles = new TClonesArray("TParticle",1000);
TDatabasePDG *pDataBase = TDatabasePDG::Instance();
//
Float_t random[6];
// Calculating vertex position per event
for (j=0;j<3;j++) origin0[j]=fOrigin[j];
time0 = fTimeOrigin;
if(fVertexSmear==kPerEvent) {
Vertex();
for (j=0;j<3;j++) origin0[j]=fVertex[j];
time0 = fTime;
}
Int_t ipa=0;
// Generating fNpart particles
fNprimaries = 0;
Int_t nGen = fNpart*ntimes;
while (ipa<nGen) {
while(1) {
//
// particle type
Int_t iPart = fIpParaFunc ? fIpParaFunc(fRandom) : fPDGcode;
Int_t iTemp = iPart;
// custom pdg codes to destinguish direct photons
if(iPart>=220000 & iPart<=220001) iPart=22;
fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
TParticlePDG *particle = pDataBase->GetParticle(iPart);
Float_t am = particle->Mass();
Rndm(random,2);
// --- For Exodus -------------------------------
Double_t awidth = particle->Width();
if(awidth>0){
TF1 rbw("rbw","pow([1],2)*pow([0],2)/(pow(x*x-[0]*[0],2)+pow(x*x*[1]/[0],2))",am-5*awidth,am+5*awidth);
rbw.SetParameter(0,am);
rbw.SetParameter(1,awidth);
am = rbw.GetRandom();
}
// -----------------------------------------------//
//
// y
ty = TMath::TanH(fYPara->GetRandom());
//
// pT
if (fAnalog == kAnalog) {
pt=fPtPara->GetRandom();
wgtp=fParentWeight;
wgtch=fChildWeight;
} else {
pt=fPtMin+random[1]*(fPtMax-fPtMin);
Double_t ptd=pt;
wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
}
xmt=sqrt(pt*pt+am*am);
if (TMath::Abs(ty)==1.) {
ty=0.;
Fatal("AliGenParam",
"Division by 0: Please check you rapidity range !");
}
//
// phi
// if(!ipa)
//phi=fEvPlane; //align first particle of each event with event plane
//else{
double v2 = fV2Para->Eval(pt);
fdNdPhi->SetParameter(0,v2);
fdNdPhi->SetParameter(1,fEvPlane);
phi=fdNdPhi->GetRandom();
// }
pl=xmt*ty/sqrt((1.-ty)*(1.+ty));
theta=TMath::ATan2(pt,pl);
// Cut on theta
if(theta<fThetaMin || theta>fThetaMax) continue;
ptot=TMath::Sqrt(pt*pt+pl*pl);
// Cut on momentum
if(ptot<fPMin || ptot>fPMax) continue;
//
p[0]=pt*TMath::Cos(phi);
p[1]=pt*TMath::Sin(phi);
p[2]=pl;
energy=TMath::Sqrt(ptot*ptot+am*am);
if(fVertexSmear==kPerTrack) {
Rndm(random,6);
for (j=0;j<3;j++) {
origin0[j]= fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
}
Rndm(random,2);
time0 = fTimeOrigin + fOsigma[2]/TMath::Ccgs()*
TMath::Cos(2*random[0]*TMath::Pi())*
TMath::Sqrt(-2*TMath::Log(random[1]));
}
// Looking at fForceDecay :
// if fForceDecay != none Primary particle decays using
// AliPythia and children are tracked by GEANT
//
// if fForceDecay == none Primary particle is tracked by GEANT
// (In the latest, make sure that GEANT actually does all the decays you want)
//
Bool_t decayed = kFALSE;
if (fForceDecay != kNoDecay) {
// Using lujet to decay particle
TLorentzVector pmom(p[0], p[1], p[2], energy);
fDecayer->Decay(iPart,&pmom);
//
// select decay particles
Int_t np=fDecayer->ImportParticles(particles);
iPart=iTemp;
if(iPart>=220000 & iPart<=220001){
TParticle *gamma = (TParticle *)particles->At(0);
gamma->SetPdgCode(iPart);
np=VirtualGammaPairProduction(particles,np);
}
if(fForceConv) np=ForceGammaConversion(particles,np);
// Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
if (fGeometryAcceptance)
if (!CheckAcceptanceGeometry(np,particles)) continue;
Int_t ncsel=0;
Int_t pFlag [np];
Int_t pParent [np];
Int_t pSelected[np];
Int_t trackIt [np];
for (i=0; i<np; i++) {
pFlag[i] = 0;
pSelected[i] = 0;
pParent[i] = -1;
}
if (np >1) {
decayed = kTRUE;
TParticle* iparticle = 0;
Int_t ipF, ipL;
for (i = 1; i<np ; i++) {
trackIt[i] = 1;
iparticle = (TParticle *) particles->At(i);
Int_t kf = iparticle->GetPdgCode();
Int_t ks = iparticle->GetStatusCode();
// flagged particle
if(!fPreserveFullDecayChain){
if (pFlag[i] == 1) {
ipF = iparticle->GetFirstDaughter() + fIncFortran;
ipL = iparticle->GetLastDaughter() + fIncFortran;
if (ipF > 0) for (j=ipF; j<=ipL; j++) pFlag[j]=1;
continue;
}
}
// flag decay products of particles with long life-time (c tau > .3 mum)
if (ks != 1) {
// TParticlePDG *particle = pDataBase->GetParticle(kf);
Double_t lifeTime = fDecayer->GetLifetime(kf);
// Double_t mass = particle->Mass();
// Double_t width = particle->Width();
if (lifeTime > (Double_t) fMaxLifeTime) {
ipF = iparticle->GetFirstDaughter() + fIncFortran;
ipL = iparticle->GetLastDaughter() + fIncFortran;
if (ipF > 0) for (j=ipF; j<=ipL; j++) pFlag[j]=1;
} else{
trackIt[i] = 0;
pSelected[i] = 1;
}
} // ks==1 ?
//
// children
if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[i]){
if (fCutOnChild) {
pc[0]=iparticle->Px();
pc[1]=iparticle->Py();
pc[2]=iparticle->Pz();
Bool_t childok = KinematicSelection(iparticle, 1);
if(childok) {
pSelected[i] = 1;
ncsel++;
} else {
if(!fKeepIfOneChildSelected){
ncsel=-1;
break;
}
} // child kine cuts
} else {
pSelected[i] = 1;
ncsel++;
} // if child selection
} // select muon
} // decay particle loop
} // if decay products
Int_t iparent;
if (fKeepParent || (fCutOnChild && ncsel >0) || !fCutOnChild){
//
// Parent
// --- For Exodus --------------------------------//
//PushTrack(0, -1, iPart, p, origin0, polar, time0, kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
PushTrack(0, -1, iPart, p[0],p[1],p[2],energy,origin0[0],origin0[1],origin0[2],time0,polar[0],polar[1],polar[2],kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
// -----------------------------------------------//
pParent[0] = nt;
KeepTrack(nt);
fNprimaries++;
//but count is as "generated" particle" only if it produced child(s) within cut
if ((fCutOnChild && ncsel >0) || !fCutOnChild) {
ipa++;
}
//
// Decay Products
//
for (i = 1; i < np; i++) {
if (pSelected[i]) {
TParticle* iparticle = (TParticle *) particles->At(i);
Int_t kf = iparticle->GetPdgCode();
Int_t ksc = iparticle->GetStatusCode();
Int_t jpa = iparticle->GetFirstMother() + fIncFortran;
Double_t weight = iparticle->GetWeight();
och[0] = origin0[0]+iparticle->Vx();
och[1] = origin0[1]+iparticle->Vy();
och[2] = origin0[2]+iparticle->Vz();
pc[0] = iparticle->Px();
pc[1] = iparticle->Py();
pc[2] = iparticle->Pz();
Double_t ec = iparticle->Energy();
if (jpa > -1) {
iparent = pParent[jpa];
} else {
iparent = -1;
}
PushTrack(fTrackIt * trackIt[i], iparent, kf, pc[0], pc[1], pc[2], ec,
och[0], och[1], och[2], time0 + iparticle->T(),
polar[0], polar[1], polar[2], kPDecay, nt, weight*wgtch, ksc);
// PushTrack(fTrackIt * trackIt[i], iparent, kf,
// pc, och, polar,
// time0 + iparticle->T(), kPDecay, nt, weight*wgtch, ksc);
pParent[i] = nt;
KeepTrack(nt);
fNprimaries++;
} // Selected
} // Particle loop
} // Decays by Lujet
particles->Clear();
// kinematic selection
} else { // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
PushTrack(fTrackIt, -1, iPart, p[0], p[1], p[2], energy,
origin0[0], origin0[1], origin0[2], time0,
polar[0], polar[1], polar[2],
kPPrimary, nt, wgtp, 1);
// gAlice->GetMCApp()->
// PushTrack(fTrackIt,-1,iPart,p,origin0,polar,time0,kPPrimary,nt,wgtp, 1);
ipa++;
fNprimaries++;
}
break;
} // while
} // event loop
SetHighWaterMark(nt);
AliGenEventHeader* header = new AliGenEventHeader("PARAM");
header->SetPrimaryVertex(fVertex);
header->SetInteractionTime(fTime);
header->SetNProduced(fNprimaries);
AddHeader(header);
}
//____________________________________________________________________________________
Float_t AliGenParam::GetRelativeArea(Float_t ptMin, Float_t ptMax, Float_t yMin, Float_t yMax, Float_t phiMin, Float_t phiMax)
{
//
// Normalisation for selected kinematic region
//
#if ROOT_VERSION_CODE < ROOT_VERSION(5,99,0)
Float_t ratio =
fPtPara->Integral(ptMin,ptMax,(Double_t *)0,1.e-6) / fPtPara->Integral( fPtPara->GetXmin(), fPtPara->GetXmax(),(Double_t *)0,1.e-6) *
fYPara->Integral(yMin,yMax,(Double_t *)0,1.e-6)/fYPara->Integral(fYPara->GetXmin(),fYPara->GetXmax(),(Double_t *)0,1.e-6) *
(phiMax-phiMin)/360.;
#else
Float_t ratio =
fPtPara->Integral(ptMin,ptMax,1.e-6) / fPtPara->Integral( fPtPara->GetXmin(), fPtPara->GetXmax(),1.e-6) *
fYPara->Integral(yMin,yMax,1.e-6)/fYPara->Integral(fYPara->GetXmin(),fYPara->GetXmax(),1.e-6) *
(phiMax-phiMin)/360.;
#endif
return TMath::Abs(ratio);
}
//____________________________________________________________________________________
void AliGenParam::Draw( const char * /*opt*/)
{
//
// Draw the pT and y Distributions
//
TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
c0->Divide(2,1);
c0->cd(1);
fPtPara->Draw();
fPtPara->GetHistogram()->SetXTitle("p_{T} (GeV)");
c0->cd(2);
fYPara->Draw();
fYPara->GetHistogram()->SetXTitle("y");
}