fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
- fForceConv(kFALSE)
+ fForceConv(kFALSE),
+ fKeepParent(kFALSE),
+ fKeepIfOneChildSelected(kFALSE)
{
// Default constructor
}
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
- fForceConv(kFALSE)
+ fForceConv(kFALSE),
+ fKeepParent(kFALSE),
+ fKeepIfOneChildSelected(kFALSE)
{
// Constructor using number of particles parameterisation id and library
fName = "Param";
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
- fForceConv(kFALSE)
+ fForceConv(kFALSE),
+ fKeepParent(kFALSE),
+ fKeepIfOneChildSelected(kFALSE)
{
// Constructor using parameterisation id and number of particles
//
fDeltaPt(0.01),
fSelectAll(kFALSE),
fDecayer(0),
- fForceConv(kFALSE)
+ fForceConv(kFALSE),
+ fKeepParent(kFALSE),
+ fKeepIfOneChildSelected(kFALSE)
{
// Constructor
// Gines Martinez 1/10/99
int solvDim=0;
double tmp=abc[0];
for(int i=0; i<3; i++)
- if(abs(abc[i])>tmp){
+ if(fabs(abc[i])>tmp){
solvDim=i;
- tmp=abs(abc[i]);
+ tmp=fabs(abc[i]);
}
xyz[solvDim]=(-abc[(1+solvDim)%3]-abc[(2+solvDim)%3])/abc[(0+solvDim)%3];
return res;
}
-double AliGenParam::ScreenFunc1(double d){
- if(d>1)
- return 21.12-4.184*log(d+0.952);
+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 20.867-3.242*d+0.652*d*d;
+ return 42.392 - screenVariable * (7.796 - 1.961 * screenVariable);
}
-double AliGenParam::ScreenFunc2(double d){
- if(d>1)
- return 21.12-4.184*log(d+0.952);
+double AliGenParam::ScreenFunction2(double screenVariable){
+ if(screenVariable>1)
+ return 42.24 - 8.368 * log(screenVariable + 0.952);
else
- return 20.209-1.93*d-0.086*d*d;
+ return 41.405 - screenVariable * (5.828 - 0.8945 * screenVariable);
}
-double AliGenParam::EnergyFraction(double Z, double E){
- double e0=0.000511/E;
+double AliGenParam::RandomEnergyFraction(double Z, double photonEnergy){
double aZ=Z/137.036;
- double dmin=ScreenVar(Z,e0,0.5);
+ 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);
- double Fz=8*log(Z)/3;
- if(E>0.05)
- Fz+=8*fcZ;
- double dmax=exp((42.24-Fz)/8.368)-0.952;
- if(!(dmax>dmin))
- return fRandom->Uniform(e0,0.5);
-
- double e1=0.5-0.5*sqrt(1-dmin/dmax);
- double emin=TMath::Max(e0,e1);
+ 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 normval=1/(0.5*(ScreenFunc1(dmin)-0.5*Fz)+0.1666667*(ScreenFunc2(dmin)-0.5*Fz));
+Double_t AliGenParam::RandomMass(Double_t mh){
while(true){
- double y=fRandom->Uniform(emin,1);
- double eps=y*(0.38453+y*(0.10234+y*(0.026072+y*(0.014367-0.027313*y)))); //inverse to the enveloping cumulative probability distribution
- double val=fRandom->Uniform(0,2.12*(eps*eps-eps)+1.53); //enveloping probability density
- double d=ScreenVar(Z,e0,eps);
- double bh=((eps*eps)+(1-eps)*(1-eps))*(ScreenFunc1(d)-0.5*Fz)+0.6666667*eps*(1-eps)*(ScreenFunc2(d)-0.5*Fz);
- bh*=normval;
- if(val<bh)
- return eps;
+ 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;
}
}
-double AliGenParam::PolarAngle(double E){
- float rand[3];
- AliRndm rndm;
- rndm.Rndm(rand,3);
- double u=-8*log(rand[1]*rand[2])/5;
- if(!(rand[0]<9.0/36))
- u/=3;
- return u*0.000511/E;
+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()!=220000) 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) continue;
-
+ if(gamma->Energy()<0.001022) continue;
TVector3 gammaV3(gamma->Px(),gamma->Py(),gamma->Pz());
- Float_t az=fRandom->Uniform(TMath::Pi()*2);
- double frac=EnergyFraction(1,gamma->Energy());
+ double frac=RandomEnergyFraction(1,gamma->Energy());
double Ee1=frac*gamma->Energy();
double Ee2=(1-frac)*gamma->Energy();
- double Pe1=Ee1;//sqrt(Ee1*Ee1-0.000511*0.000511);
- double Pe2=Ee2;//sqrt(Ee2*Ee2-0.000511*0.000511);
+ 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);
- e1V3.Rotate(PolarAngle(Ee1),rotAxis);
+ double u=RandomPolarAngle();
+ e1V3.Rotate(u/Ee1,rotAxis);
e1V3=e1V3.Unit();
e1V3*=Pe1;
TVector3 e2V3(gammaV3);
- e2V3.Rotate(-PolarAngle(Ee2),rotAxis);
+ e2V3.Rotate(-u/Ee2,rotAxis);
e2V3=e2V3.Unit();
e2V3*=Pe2;
// gamma = new TParticle(*gamma);
new((*particles)[nPartNew]) TParticle(-11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, TLorentzVector(e2V3,Ee2), vtx);
nPartNew++;
}
- // particles->Compress();
- return particles->GetEntriesFast();
+ return nPartNew;
}
//____________________________________________________________
{
// Initialisation
- if (gMC) fDecayer = gMC->GetDecayer();
+ if (TVirtualMC::GetMC()) fDecayer = TVirtualMC::GetMC()->GetDecayer();
//Begin_Html
/*
<img src="picts/AliGenParam.gif">
//
// particle type
Int_t iPart = fIpParaFunc(fRandom);
+ Int_t iTemp = iPart;
+
+ // custom pdg codes for to destinguish direct photons
+ if(iPart==220000) iPart=22;
+
fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;
TParticlePDG *particle = pDataBase->GetParticle(iPart);
Float_t am = particle->Mass();
//
// y
ty = TMath::TanH(fYPara->GetRandom());
+
//
// pT
if (fAnalog == kAnalog) {
p[0]=pt*TMath::Cos(phi);
p[1]=pt*TMath::Sin(phi);
p[2]=pl;
+
if(fVertexSmear==kPerTrack) {
Rndm(random,6);
for (j=0;j<3;j++) {
// select decay particles
Int_t np=fDecayer->ImportParticles(particles);
+ iPart=iTemp;
+ if(iPart==220000){
+ TParticle *gamma = (TParticle *)particles->At(0);
+ gamma->SetPdgCode(iPart);
+ np=VirtualGammaPairProduction(particles,np);
+ }
if(fForceConv) np=ForceGammaConversion(particles,np);
- // for(int iPart=0; iPart<np; iPart++){
- // TParticle *gamma = (TParticle *) particles->At(iPart);
- // printf("%i %i:", iPart, gamma->GetPdgCode());
- // printf("%i %i %i|",gamma->GetFirstMother(),gamma->GetFirstDaughter(),gamma->GetLastDaughter());
- // }
-
// Selecting GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
if (fGeometryAcceptance)
if (!CheckAcceptanceGeometry(np,particles)) continue;
pSelected[i] = 1;
ncsel++;
} else {
- ncsel=-1;
- break;
+ if(!fKeepIfOneChildSelected){
+ ncsel=-1;
+ break;
+ }
} // child kine cuts
} else {
pSelected[i] = 1;
} // if decay products
Int_t iparent;
- if ((fCutOnChild && ncsel >0) || !fCutOnChild){
- ipa++;
+
+ if (fKeepParent || (fCutOnChild && ncsel >0) || !fCutOnChild){
//
// Parent
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
//
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff