+++ /dev/null
-/**************************************************************************
- * 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. *
- **************************************************************************/
-
-//-----------------------------------------------------------------//
-// //
-// Implementation of the TOF PID class //
-// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch //
-// //
-//-----------------------------------------------------------------//
-
-#include "TMath.h"
-#include "AliLog.h"
-
-#include "AliESDtrack.h"
-#include "AliESDEvent.h"
-
-#include "AliTOFpidESD.h"
-
-ClassImp(AliTOFpidESD)
-
-//_________________________________________________________________________
-AliTOFpidESD::AliTOFpidESD():
- fSigma(0),
- fRange(0),
- fPmax(0), // zero at 0.5 GeV/c for pp
- fTime0(0)
-{
-}
-//_________________________________________________________________________
-AliTOFpidESD::AliTOFpidESD(Double_t *param):
- fSigma(param[0]),
- fRange(param[1]),
- fPmax(0), // zero at 0.5 GeV/c for pp
- fTime0(0)
-{
- //
- // The main constructor
- //
- //
-
- //fPmax=TMath::Exp(-0.5*3*3)/fSigma; // ~3 sigma at 0.5 GeV/c for PbPb
-}
-
-//_________________________________________________________________________
-Double_t
-AliTOFpidESD::GetMismatchProbability(Double_t p, Double_t mass) const {
- //
- // Returns the probability of mismatching
- // assuming 1/(p*beta)^2 scaling
- //
- const Double_t km=0.5; // "reference" momentum (GeV/c)
-
- Double_t ref2=km*km*km*km/(km*km + mass*mass);// "reference" (p*beta)^2
- Double_t p2beta2=p*p*p*p/(p*p + mass*mass);
-
- return fPmax*ref2/p2beta2;
-}
-
-//_________________________________________________________________________
-Int_t AliTOFpidESD::MakePID(AliESDEvent *event, Double_t timeZero)
-{
- //
- // This function calculates the "detector response" PID probabilities
- // Just for a bare hint...
-
- AliDebug(1,Form("TOF PID Parameters: Sigma (ps)= %f, Range= %f",fSigma,fRange));
- AliDebug(1,"++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ \n");
-
- fTime0=timeZero;
- return MakePID(event);
-}
-
-//_________________________________________________________________________
-Int_t AliTOFpidESD::MakePID(AliESDEvent *event)
-{
- //
- // This function calculates the "detector response" PID probabilities
- // Just for a bare hint...
-
- Int_t ntrk=event->GetNumberOfTracks();
- AliESDtrack **tracks=new AliESDtrack*[ntrk];
-
- Int_t i;
- for (i=0; i<ntrk; i++) {
- AliESDtrack *t=event->GetTrack(i);
- tracks[i]=t;
- }
-
- for (i=0; i<ntrk; i++) {
- AliESDtrack *t=tracks[i];
- if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue;
- if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue;
-
- Double_t time[AliPID::kSPECIES];
- if (!ExpectedSignals(t,time,AliPID::kSPECIES)) continue;
- Double_t sigma[AliPID::kSPECIES];
- if (!ExpectedSigmas(t,sigma,AliPID::kSPECIES)) continue;
-
- AliDebug(2,Form("Expected TOF signals [ps]: %f %f %f %f %f",
- GetExpectedSignal(t,AliPID::kElectron),
- GetExpectedSignal(t,AliPID::kMuon),
- GetExpectedSignal(t,AliPID::kPion),
- GetExpectedSignal(t,AliPID::kKaon),
- GetExpectedSignal(t,AliPID::kProton)
- ));
-
- AliDebug(2,Form("Expected TOF std deviations [ps]: %f %f %f %f %f",
- GetExpectedSigma(t,AliPID::kElectron),
- GetExpectedSigma(t,AliPID::kMuon),
- GetExpectedSigma(t,AliPID::kPion),
- GetExpectedSigma(t,AliPID::kKaon),
- GetExpectedSigma(t,AliPID::kProton)
- ));
-
- AliDebug(2,Form("Expected TOF std deviations [number of expected sigmas]: %f %f %f %f %f",
- GetNumberOfSigmas(t,AliPID::kElectron),
- GetNumberOfSigmas(t,AliPID::kMuon),
- GetNumberOfSigmas(t,AliPID::kPion),
- GetNumberOfSigmas(t,AliPID::kKaon),
- GetNumberOfSigmas(t,AliPID::kProton)
- ));
-
- Double_t tof = t->GetTOFsignal() - fTime0;
-
- Double_t p[AliPID::kSPECIES];
- Bool_t mismatch = kTRUE, heavy = kTRUE;
- for (Int_t j=0; j<AliPID::kSPECIES; j++) {
- Double_t sig = sigma[j];
- if (TMath::Abs(tof-time[j]) > fRange*sig) {
- p[j] = TMath::Exp(-0.5*fRange*fRange)/sig;
- } else
- p[j] = TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sig*sig))/sig;
-
- // Check the mismatching
- Double_t mass = AliPID::ParticleMass(j);
- Double_t pm = GetMismatchProbability(t->GetP(),mass);
- if (p[j]>pm) mismatch = kFALSE;
-
- // Check for particles heavier than (AliPID::kSPECIES - 1)
- if (tof < (time[j] + fRange*sig)) heavy=kFALSE;
-
- }
-
- if (mismatch)
- for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES;
-
- t->SetTOFpid(p);
-
- if (heavy) t->ResetStatus(AliESDtrack::kTOFpid);
-
- }
-
- delete[] tracks;
-
- return 0;
-}
-
-//_________________________________________________________________________
-Bool_t AliTOFpidESD::ExpectedSignals(const AliESDtrack *t,
- Double_t s[],Int_t n) const
-{
- //
- // Return the expected PID signals for the involved particle species
- //
-
- if (n > AliPID::kSPECIESN) return kFALSE;
- if ( !t->IsOn(AliESDtrack::kTIME) ) return kFALSE;
-
- Double_t time[AliPID::kSPECIESN];
- t->GetIntegratedTimes(time);
- for (Int_t i=0; i<n; i++) s[i]=time[i];
- return kTRUE;
-}
-
-//_________________________________________________________________________
-Bool_t AliTOFpidESD::ExpectedSigmas(const AliESDtrack *t,
- Double_t s[],Int_t n) const
-{
- //
- // Return the expected sigma of PID signals for the involved
- // particle species.
- // This approximate (but reasonable) formula takes into account the
- // relative momentum resolution.
- //
-
- Double_t time[AliPID::kSPECIESN];
- if ( !ExpectedSignals(t,time,n) ) return kFALSE;
-
- Double_t mom = t->GetP();
- Double_t dpp = 0.01; //mean relative pt resolution;
- if (mom>0.5) dpp = 0.01*mom;
- for (Int_t i=0; i<n; i++) {
- Double_t mass = AliPID::ParticleMass(i);
- Double_t sigma = dpp*time[i]/(1.+ mom*mom/(mass*mass));
- s[i] = TMath::Sqrt(sigma*sigma + fSigma*fSigma);
- }
- return kTRUE;
-}
-
-//_________________________________________________________________________
-Bool_t AliTOFpidESD::NumberOfSigmas(const AliESDtrack *t,
- Double_t s[],Int_t n) const
-{
- //
- // Returns the deviation of the actual PID signal from the expected
- // signal, in units of expected sigmas.
- //
-
- Double_t time[AliPID::kSPECIESN];
- if ( !ExpectedSignals(t,time,n) ) return kFALSE;
-
- if ( !ExpectedSigmas(t,s,n) ) return kFALSE;
-
- Double_t tof = t->GetTOFsignal() - fTime0;
- for (Int_t i=0; i<n; i++) s[i] = (time[i]-tof)/s[i];
-
- return kTRUE;
-}
-
-//_________________________________________________________________________
- Double_t AliTOFpidESD::GetExpectedSignal(const AliESDtrack *t,
- AliPID::EParticleType n) const
-{
- //
- // Return the expected PID signal for the specified particle type.
- // If the operation is not possible, return a negative value.
- //
-
- if (Int_t(n) >= AliPID::kSPECIESN) return -1.;
- if ( !t->IsOn(AliESDtrack::kTIME) ) return -1.;
-
- Double_t time[AliPID::kSPECIESN];
- t->GetIntegratedTimes(time);
-
- return time[n];
-}
-
-//_________________________________________________________________________
- Double_t AliTOFpidESD::GetExpectedSigma(const AliESDtrack *t,
- AliPID::EParticleType n) const
-{
- //
- // Return the expected sigma of the PID signal for the specified
- // particle type.
- // If the operation is not possible, return a negative value.
- //
-
- Double_t time[AliPID::kSPECIESN];
- if ( !ExpectedSignals(t,time,AliPID::kSPECIESN) ) return -1.;
-
- Double_t mom = t->GetP();
- Double_t dpp = 0.01; //mean relative pt resolution;
- if (mom>0.5) dpp = 0.01*mom;
-
- Double_t mass = AliPID::ParticleMass(n);
- Double_t sigma = dpp*time[n]/(1.+ mom*mom/(mass*mass));
-
- return TMath::Sqrt(sigma*sigma + fSigma*fSigma);
-}
-
-//_________________________________________________________________________
- Double_t AliTOFpidESD::GetNumberOfSigmas(const AliESDtrack *t,
- AliPID::EParticleType n) const
-{
- //
- // Returns the deviation of the actual PID signal from the expected
- // signal for the specified particle type, in units of expected
- // sigmas.
- // If the operation is not possible, return a negative value.
- //
-
- Double_t time=GetExpectedSignal(t,n);;
- if (time < 0.) return -1.;
-
- Double_t sigma=GetExpectedSigma(t,n);
- if (sigma < 0.) return -1;
-
- Double_t tof=t->GetTOFsignal() - fTime0;
- return (time-tof)/sigma;
-}
git://git.uio.no / u / mrichter / AliRoot.git / commitdiff