#include "AliLog.h"
#include "AliESDtrack.h"
-#include "AliESD.h"
+#include "AliESDEvent.h"
#include "AliTOFpidESD.h"
ClassImp(AliTOFpidESD)
//_________________________________________________________________________
- AliTOFpidESD::AliTOFpidESD():
- fN(-1),
- fEventN(-1),
+AliTOFpidESD::AliTOFpidESD():
fSigma(0),
- fRange(0)
+ fRange(0),
+ fPmax(0), // zero at 0.5 GeV/c for pp
+ fTime0(0)
{
}
//_________________________________________________________________________
AliTOFpidESD::AliTOFpidESD(Double_t *param):
- fN(0),
- fEventN(0),
- fSigma(0),
- fRange(0)
- {
+ fSigma(param[0]),
+ fRange(param[1]),
+ fPmax(0), // zero at 0.5 GeV/c for pp
+ fTime0(0)
+{
//
// The main constructor
//
- fSigma=param[0];
- fRange=param[1];
+ //
+
+ //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(AliESD *event, Double_t timeZero)
+Int_t AliTOFpidESD::MakePID(AliESDEvent *event, Double_t timeZero)
{
//
// This function calculates the "detector response" PID probabilities
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];
AliESDtrack *t=tracks[i];
if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue;
if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue;
- Double_t tof=t->GetTOFsignal()-timeZero;
- Double_t time[10]; t->GetIntegratedTimes(time);
- Double_t p[10];
- Double_t mom=t->GetP();
+
+ 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 mass=AliPID::ParticleMass(j);
- Double_t dpp=0.01; //mean relative pt resolution;
- if (mom>0.5) dpp=0.01*mom;
- Double_t sigma=dpp*time[j]/(1.+ mom*mom/(mass*mass));
- sigma=TMath::Sqrt(sigma*sigma + fSigma*fSigma);
- if (TMath::Abs(tof-time[j]) > fRange*sigma) {
- p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
- continue;
- }
- p[j]=TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sigma*sigma))/sigma;
+ 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;
}
//_________________________________________________________________________
-Int_t AliTOFpidESD::MakePID(AliESD *event)
+Bool_t AliTOFpidESD::ExpectedSignals(const AliESDtrack *t,
+ Double_t s[],Int_t n) const
{
//
- // This function calculates the "detector response" PID probabilities
- // Just for a bare hint...
+ // Return the expected PID signals for the involved particle species
+ //
- Int_t ntrk=event->GetNumberOfTracks();
- AliESDtrack **tracks=new AliESDtrack*[ntrk];
+ if (n > AliPID::kSPECIESN) return kFALSE;
+ if ( !t->IsOn(AliESDtrack::kTIME) ) return kFALSE;
- Int_t i;
- for (i=0; i<ntrk; i++) {
- AliESDtrack *t=event->GetTrack(i);
- tracks[i]=t;
- }
+ Double_t time[AliPID::kSPECIESN];
+ t->GetIntegratedTimes(time);
+ for (Int_t i=0; i<n; i++) s[i]=time[i];
+ return kTRUE;
+}
- 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 tof=t->GetTOFsignal();
- Double_t time[10]; t->GetIntegratedTimes(time);
- Double_t p[10];
- Double_t mom=t->GetP();
- for (Int_t j=0; j<AliPID::kSPECIES; j++) {
- Double_t mass=AliPID::ParticleMass(j);
- Double_t dpp=0.01; //mean relative pt resolution;
- if (mom>0.5) dpp=0.01*mom;
- Double_t sigma=dpp*time[j]/(1.+ mom*mom/(mass*mass));
- sigma=TMath::Sqrt(sigma*sigma + fSigma*fSigma);
- if (TMath::Abs(tof-time[j]) > fRange*sigma) {
- p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
- continue;
- }
- p[j]=TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sigma*sigma))/sigma;
- }
- t->SetTOFpid(p);
+//_________________________________________________________________________
+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;
+}
- delete[] tracks;
+//_________________________________________________________________________
+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;
- return 0;
+ 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 / blobdiff