#include "AliHMPIDPid.h" //class header
#include "AliHMPIDParam.h" //class header
+#include "AliHMPIDRecon.h" //class header
#include <AliESDtrack.h> //FindPid()
+#include <TRandom.h> //Resolution()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AliHMPIDPid::AliHMPIDPid():TTask("HMPIDrec","HMPIDPid")
//..
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-void AliHMPIDPid::FindPid(AliESDtrack *pTrk,Double_t *prob)
+void AliHMPIDPid::FindPid(AliESDtrack *pTrk,Int_t nsp,Double_t *prob)
{
-// Calculates probability to be a electron-muon-pion-kaon-proton
+// Calculates probability to be a electron-muon-pion-kaon-proton with the "amplitude" method
// from the given Cerenkov angle and momentum assuming no initial particle composition
// (i.e. apriory probability to be the particle of the given sort is the same for all sorts)
- AliPID ppp; //needed
- Double_t h[AliPID::kSPECIES];
+ AliPID *pPid = new AliPID();
+ Double_t thetaCerExp = pTrk->GetHMPIDsignal(); // measured thetaCherenkov
- if(pTrk->GetHMPIDsignal()<=0){//HMPID does not find anything reasonable for this track, assign 0.2 for all species
- for(Int_t iPart=0;iPart<AliPID::kSPECIES;iPart++) prob[iPart]=1.0/AliPID::kSPECIES;
+ if(thetaCerExp<=0){ //HMPID does not find anything reasonable for this track, assign 0.2 for all species
+ for(Int_t iPart=0;iPart<nsp;iPart++) prob[iPart]=1.0/(Float_t)nsp;
return;
}
+
+ Double_t p[3] = {0}, pmod = 0;
+ if(pTrk->GetOuterHmpPxPyPz(p)) pmod = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]+p[2]*p[2]); // Momentum of the charged particle
+
+ else {
+ for(Int_t iPart=0;iPart<nsp;iPart++) prob[iPart]=1.0/(Float_t)nsp;
+ return;
+ }
+
+ Double_t hTot=0; // Initialize the total height of the amplitude method
+ Double_t *h = new Double_t [nsp]; // number of charged particles to be considered
- Double_t pmod = pTrk->GetP();
- Double_t hTot=0;
-
- for(Int_t iPart=0;iPart<AliPID::kSPECIES;iPart++){
- Double_t mass = AliPID::ParticleMass(iPart);
- Double_t cosThetaTh = TMath::Sqrt(mass*mass+pmod*pmod)/(AliHMPIDParam::Instance()->MeanIdxRad()*pmod);
- if(cosThetaTh<1) //calculate the height of theoretical theta ckov on the gaus of experimental one
- h[iPart] =TMath::Gaus(TMath::ACos(cosThetaTh),pTrk->GetHMPIDsignal(),TMath::Sqrt(pTrk->GetHMPIDchi2()),kTRUE);
- else //beta < 1/ref. idx. => no light at all
- h[iPart] =0 ;
+ Bool_t desert = kTRUE; // Flag to evaluate if ThetaC is far ("desert") from the given Gaussians
+
+ for(Int_t iPart=0;iPart<nsp;iPart++){ // for each particle
+
+ h[iPart] = 0; // reset the height
+ Double_t mass = pPid->ParticleMass(iPart); // with the given mass
+ Double_t cosThetaTh = TMath::Sqrt(mass*mass+pmod*pmod)/(AliHMPIDParam::Instance()->MeanIdxRad()*pmod); // evaluate the theor. Theta Cherenkov
+ if(cosThetaTh>1) continue; // no light emitted, zero height
+ Double_t thetaCerTh = TMath::ACos(cosThetaTh); // theoretical Theta Cherenkov
+ Double_t sigmaRing = Resolution(thetaCerTh,pTrk);
+
+ if(sigmaRing==0) {
+ for(Int_t jPart=0;jPart<nsp;jPart++) prob[jPart]=1.0/(Float_t)nsp;
+ return;
+ }
+
+ if(TMath::Abs(thetaCerExp-thetaCerTh)<4*sigmaRing) desert = kFALSE; //
+ h[iPart] =TMath::Gaus(thetaCerTh,thetaCerExp,sigmaRing,kTRUE);
hTot +=h[iPart]; //total height of all theoretical heights for normalization
+
}//species loop
- Double_t hMin=TMath::Gaus(pTrk->GetHMPIDsignal()-4*TMath::Sqrt(pTrk->GetHMPIDchi2()),pTrk->GetHMPIDsignal(),TMath::Sqrt(pTrk->GetHMPIDchi2()),kTRUE);//5 sigma protection
-
- for(Int_t iPart=0;iPart<AliPID::kSPECIES;iPart++) {//species loop to assign probabilities
- if(hTot>hMin) prob[iPart]=h[iPart]/hTot;
- else prob[iPart]=1.0/AliPID::kSPECIES; //all theoretical values are far away from experemental one
+ for(Int_t iPart=0;iPart<nsp;iPart++) {//species loop to assign probabilities
+
+ if(!desert) prob[iPart]=h[iPart]/hTot;
+ else prob[iPart]=1.0/(Float_t)nsp; //all theoretical values are far away from experemental one
+
}
+
+ delete [] h;
+ delete pPid ; pPid=0x0;
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Double_t AliHMPIDPid::Resolution(Double_t thetaCerTh, AliESDtrack *pTrk)
+{
+ AliHMPIDParam *pParam = AliHMPIDParam::Instance();
+
+ AliHMPIDRecon rec;
+ Float_t xRa,yRa,thRa,phRa;
+ pTrk->GetHMPIDtrk(xRa,yRa,thRa,phRa);
+ rec.SetTrack(xRa,yRa,thRa,phRa);
+ Double_t thetaMax = TMath::ACos(1./pParam->MeanIdxRad());
+ Int_t nPhots = (Int_t)(21.*TMath::Sin(thetaCerTh)*TMath::Sin(thetaCerTh)/(TMath::Sin(thetaMax)*TMath::Sin(thetaMax))+0.01);
+
+ Double_t sigmatot = 0;
+ Int_t nTrks = 20;
+ for(Int_t iTrk=0;iTrk<nTrks;iTrk++) {
+ Double_t invSigma = 0;
+ Int_t nPhotsAcc = 0;
+ for(Int_t j=0;j<nPhots;j++){
+ Double_t phi = gRandom->Rndm()*TMath::TwoPi();
+ TVector2 pos; pos=rec.TracePhot(thetaCerTh,phi);
+ if(!pParam->IsInside(pos.X(),pos.Y())) continue;
+ if(pParam->IsInDead(pos.X(),pos.Y())) continue;
+ Double_t sigma2 = pParam->Sigma2(thRa,phRa,thetaCerTh,phi);//photon candidate sigma^2
+ if(sigma2!=0) {
+ invSigma += 1./sigma2;
+ nPhotsAcc++;
+ }
+ }
+ if(invSigma!=0) sigmatot += 1./TMath::Sqrt(invSigma);
+ }
+ return sigmatot/nTrks;
+}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff