1 /**************************************************************************
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4 * Author: The ALICE Off-line Project. *
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14 **************************************************************************/
16 //-----------------------------------------------------------------//
18 // Implementation of the TOF PID class //
19 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch //
21 //-----------------------------------------------------------------//
26 #include "AliTOFPIDResponse.h"
28 ClassImp(AliTOFPIDResponse)
30 //_________________________________________________________________________
31 AliTOFPIDResponse::AliTOFPIDResponse():
33 fPmax(0), // zero at 0.5 GeV/c for pp
45 //_________________________________________________________________________
46 AliTOFPIDResponse::AliTOFPIDResponse(Double_t *param):
48 fPmax(0), // zero at 0.5 GeV/c for pp
52 // The main constructor
56 //fPmax=TMath::Exp(-0.5*3*3)/fSigma; // ~3 sigma at 0.5 GeV/c for PbPb
67 //_________________________________________________________________________
69 AliTOFPIDResponse::GetMismatchProbability(Double_t p, Double_t mass) const {
71 // Returns the probability of mismatching
72 // assuming 1/(p*beta)^2 scaling
74 const Double_t km=0.5; // "reference" momentum (GeV/c)
76 Double_t ref2=km*km*km*km/(km*km + mass*mass);// "reference" (p*beta)^2
77 Double_t p2beta2=p*p*p*p/(p*p + mass*mass);
79 return fPmax*ref2/p2beta2;
81 //_________________________________________________________________________
82 Double_t AliTOFPIDResponse::GetExpectedSigma(Float_t mom, Float_t time, Float_t mass) const {
84 // Return the expected sigma of the PID signal for the specified
86 // If the operation is not possible, return a negative value.
89 Double_t dpp=fPar[0] + fPar[1]*mom + fPar[2]*mass/mom; //mean relative pt resolution;
92 Double_t sigma = dpp*time/(1.+ mom*mom/(mass*mass));
94 Int_t index = GetMomBin(mom);
96 Double_t t0res = fT0resolution[index];
98 return TMath::Sqrt(sigma*sigma + fPar[3]*fPar[3]/mom/mom + fSigma*fSigma + t0res*t0res);
101 //_________________________________________________________________________
102 Int_t AliTOFPIDResponse::GetMomBin(Float_t p) const{
104 // Returns the momentum bin index
108 while(p > fPCutMin[i] && i < fNmomBins) i++;
113 //_________________________________________________________________________
114 void AliTOFPIDResponse::SetMomBoundary(){
116 // Set boundaries for momentum bins
131 //_________________________________________________________________________
132 Float_t AliTOFPIDResponse::GetStartTime(Float_t mom) const {
134 // Returns event_time value as estimated by TOF combinatorial algorithm
137 Int_t ibin = GetMomBin(mom);
138 return GetT0bin(ibin);
141 //_________________________________________________________________________
142 Float_t AliTOFPIDResponse::GetStartTimeRes(Float_t mom) const {
144 // Returns event_time resolution as estimated by TOF combinatorial algorithm
147 Int_t ibin = GetMomBin(mom);
148 return GetT0binRes(ibin);
151 //_________________________________________________________________________
152 Int_t AliTOFPIDResponse::GetStartTimeMask(Float_t mom) const {
154 // Returns event_time mask
157 Int_t ibin = GetMomBin(mom);
158 return GetT0binMask(ibin);