[u/mrichter/AliRoot.git] / STEER / STEERBase / AliTOFPIDResponse.cxx

/**************************************************************************
 * 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 "AliTOFPIDResponse.h"

ClassImp(AliTOFPIDResponse)

//_________________________________________________________________________
AliTOFPIDResponse::AliTOFPIDResponse(): 
  fSigma(0),
  fPmax(0),         // zero at 0.5 GeV/c for pp
  fTime0(0)
{
  fPar[0] = 0.008;
  fPar[1] = 0.008;
  fPar[2] = 0.002;
  fPar[3] = 40.0;

  // Reset T0 info
  ResetT0info();
  SetMomBoundary();
}
//_________________________________________________________________________
AliTOFPIDResponse::AliTOFPIDResponse(Double_t *param):
  fSigma(param[0]),
  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 

  fPar[0] = 0.008;
  fPar[1] = 0.008;
  fPar[2] = 0.002;
  fPar[3] = 40.0;

  // Reset T0 info
  ResetT0info();
  SetMomBoundary();
}
//_________________________________________________________________________
Double_t 
AliTOFPIDResponse::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;
}
//_________________________________________________________________________
Double_t AliTOFPIDResponse::GetExpectedSigma(Float_t mom, Float_t time, Float_t mass) const {
  //
  // Return the expected sigma of the PID signal for the specified
  // particle mass/Z.
  // If the operation is not possible, return a negative value.
  //

  Double_t dpp=fPar[0] + fPar[1]*mom + fPar[2]*mass/mom;      //mean relative pt resolution;

 
  Double_t sigma = dpp*time/(1.+ mom*mom/(mass*mass));
  
  Int_t index = GetMomBin(mom);

  Double_t t0res = fT0resolution[index];

  return TMath::Sqrt(sigma*sigma + fPar[3]*fPar[3]/mom/mom + fSigma*fSigma + t0res*t0res);

}
//_________________________________________________________________________
Double_t AliTOFPIDResponse::GetExpectedSigma(Float_t mom, Float_t time, AliPID::EParticleType  type) 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 mass = AliPID::ParticleMassZ(type);
  Double_t dpp=fPar[0] + fPar[1]*mom + fPar[2]*mass/mom;      //mean relative pt resolution;

 
  Double_t sigma = dpp*time/(1.+ mom*mom/(mass*mass));
  
  Int_t index = GetMomBin(mom);

  Double_t t0res = fT0resolution[index];

  return TMath::Sqrt(sigma*sigma + fPar[3]*fPar[3]/mom/mom + fSigma*fSigma + t0res*t0res);

}
//_________________________________________________________________________
Double_t AliTOFPIDResponse::GetExpectedSignal(const AliVTrack* track,AliPID::EParticleType type) const {
  //
  // Return the expected signal of the PID signal for the particle type
  // If the operation is not possible, return a negative value.
  //
  Double_t expt[5];
  track->GetIntegratedTimes(expt);
  if (type<=AliPID::kProton) return expt[type];
  else {
    Double_t p = track->P();
    Double_t massZ = AliPID::ParticleMassZ(type);
    return expt[0]/p*massZ*TMath::Sqrt(1.+p*p/massZ/massZ);
  }
}
//_________________________________________________________________________
Int_t AliTOFPIDResponse::GetMomBin(Float_t p) const{
  //
  // Returns the momentum bin index
  //

  Int_t i=0;
  while(p > fPCutMin[i] && i < fNmomBins) i++;
  if(i > 0) i--;

  return i;
}
//_________________________________________________________________________
void AliTOFPIDResponse::SetMomBoundary(){
  //
  // Set boundaries for momentum bins
  //

  fPCutMin[0] = 0.3;
  fPCutMin[1] = 0.5;
  fPCutMin[2] = 0.6;
  fPCutMin[3] = 0.7;
  fPCutMin[4] = 0.8;
  fPCutMin[5] = 0.9;
  fPCutMin[6] = 1;
  fPCutMin[7] = 1.2;
  fPCutMin[8] = 1.5;
  fPCutMin[9] = 2;
  fPCutMin[10] = 3;  
}
//_________________________________________________________________________
Float_t AliTOFPIDResponse::GetStartTime(Float_t mom) const {
  //
  // Returns event_time value as estimated by TOF combinatorial algorithm
  //

  Int_t ibin = GetMomBin(mom);
  return GetT0bin(ibin);

}
//_________________________________________________________________________
Float_t AliTOFPIDResponse::GetStartTimeRes(Float_t mom) const {
  //
  // Returns event_time resolution as estimated by TOF combinatorial algorithm
  //

  Int_t ibin = GetMomBin(mom);
  return GetT0binRes(ibin);

}
//_________________________________________________________________________
Int_t AliTOFPIDResponse::GetStartTimeMask(Float_t mom) const {
  //
  // Returns event_time mask
  //

  Int_t ibin = GetMomBin(mom);
  return GetT0binMask(ibin);

}
Commit	Line	Data
10d100d4	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	//-----------------------------------------------------------------//
	17	// //
	18	// Implementation of the TOF PID class //
	19	// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch //
	20	// //
	21	//-----------------------------------------------------------------//
	22
	23	#include "TMath.h"
	24	#include "AliLog.h"
	25
	26	#include "AliTOFPIDResponse.h"
	27
	28	ClassImp(AliTOFPIDResponse)
	29
	30	//_________________________________________________________________________
	31	AliTOFPIDResponse::AliTOFPIDResponse():
	32	fSigma(0),
	33	fPmax(0), // zero at 0.5 GeV/c for pp
	34	fTime0(0)
	35	{
679de35e	36	fPar[0] = 0.008;
	37	fPar[1] = 0.008;
	38	fPar[2] = 0.002;
	39	fPar[3] = 40.0;
95ad1018	40
6c68754e	41	// Reset T0 info
	42	ResetT0info();
	43	SetMomBoundary();
10d100d4	44	}
	45	//_________________________________________________________________________
	46	AliTOFPIDResponse::AliTOFPIDResponse(Double_t *param):
	47	fSigma(param[0]),
	48	fPmax(0), // zero at 0.5 GeV/c for pp
	49	fTime0(0)
	50	{
	51	//
	52	// The main constructor
	53	//
	54	//
	55
	56	//fPmax=TMath::Exp(-0.533)/fSigma; // ~3 sigma at 0.5 GeV/c for PbPb
6c68754e	57
679de35e	58	fPar[0] = 0.008;
	59	fPar[1] = 0.008;
	60	fPar[2] = 0.002;
	61	fPar[3] = 40.0;
95ad1018	62
6c68754e	63	// Reset T0 info
	64	ResetT0info();
	65	SetMomBoundary();
10d100d4	66	}
	67	//_________________________________________________________________________
	68	Double_t
	69	AliTOFPIDResponse::GetMismatchProbability(Double_t p, Double_t mass) const {
	70	//
	71	// Returns the probability of mismatching
	72	// assuming 1/(p*beta)^2 scaling
	73	//
	74	const Double_t km=0.5; // "reference" momentum (GeV/c)
	75
	76	Double_t ref2=kmkmkmkm/(kmkm + massmass);// "reference" (pbeta)^2
	77	Double_t p2beta2=pppp/(pp + mass*mass);
	78
	79	return fPmax*ref2/p2beta2;
	80	}
	81	//_________________________________________________________________________
	82	Double_t AliTOFPIDResponse::GetExpectedSigma(Float_t mom, Float_t time, Float_t mass) const {
	83	//
	84	// Return the expected sigma of the PID signal for the specified
67376d1d	85	// particle mass/Z.
10d100d4	86	// If the operation is not possible, return a negative value.
	87	//
	88
95ad1018	89	Double_t dpp=fPar[0] + fPar[1]mom + fPar[2]mass/mom; //mean relative pt resolution;
10d100d4	90
	91
	92	Double_t sigma = dpptime/(1.+ mommom/(mass*mass));
6c68754e	93
	94	Int_t index = GetMomBin(mom);
	95
	96	Double_t t0res = fT0resolution[index];
	97
95ad1018	98	return TMath::Sqrt(sigmasigma + fPar[3]fPar[3]/mom/mom + fSigmafSigma + t0rest0res);
10d100d4	99
10d100d4	100	}
6c68754e	101	//_________________________________________________________________________
67376d1d	102	Double_t AliTOFPIDResponse::GetExpectedSigma(Float_t mom, Float_t time, AliPID::EParticleType type) const {
	103	//
	104	// Return the expected sigma of the PID signal for the specified
	105	// particle type.
	106	// If the operation is not possible, return a negative value.
	107	//
	108
	109	Double_t mass = AliPID::ParticleMassZ(type);
	110	Double_t dpp=fPar[0] + fPar[1]mom + fPar[2]mass/mom; //mean relative pt resolution;
	111
	112
	113	Double_t sigma = dpptime/(1.+ mommom/(mass*mass));
	114
	115	Int_t index = GetMomBin(mom);
	116
	117	Double_t t0res = fT0resolution[index];
	118
	119	return TMath::Sqrt(sigmasigma + fPar[3]fPar[3]/mom/mom + fSigmafSigma + t0rest0res);
	120
	121	}
	122	//_________________________________________________________________________
	123	Double_t AliTOFPIDResponse::GetExpectedSignal(const AliVTrack* track,AliPID::EParticleType type) const {
	124	//
	125	// Return the expected signal of the PID signal for the particle type
	126	// If the operation is not possible, return a negative value.
	127	//
	128	Double_t expt[5];
	129	track->GetIntegratedTimes(expt);
	130	if (type<=AliPID::kProton) return expt[type];
	131	else {
	132	Double_t p = track->P();
	133	Double_t massZ = AliPID::ParticleMassZ(type);
	134	return expt[0]/pmassZTMath::Sqrt(1.+p*p/massZ/massZ);
	135	}
	136	}
	137	//_________________________________________________________________________
6c68754e	138	Int_t AliTOFPIDResponse::GetMomBin(Float_t p) const{
f858b00e	139	//
	140	// Returns the momentum bin index
	141	//
	142
6c68754e	143	Int_t i=0;
	144	while(p > fPCutMin[i] && i < fNmomBins) i++;
	145	if(i > 0) i--;
10d100d4	146
6c68754e	147	return i;
	148	}
	149	//_________________________________________________________________________
	150	void AliTOFPIDResponse::SetMomBoundary(){
f858b00e	151	//
	152	// Set boundaries for momentum bins
	153	//
	154
6c68754e	155	fPCutMin[0] = 0.3;
	156	fPCutMin[1] = 0.5;
	157	fPCutMin[2] = 0.6;
	158	fPCutMin[3] = 0.7;
	159	fPCutMin[4] = 0.8;
	160	fPCutMin[5] = 0.9;
	161	fPCutMin[6] = 1;
	162	fPCutMin[7] = 1.2;
	163	fPCutMin[8] = 1.5;
	164	fPCutMin[9] = 2;
	165	fPCutMin[10] = 3;
	166	}
f858b00e	167	//_________________________________________________________________________
7170298c	168	Float_t AliTOFPIDResponse::GetStartTime(Float_t mom) const {
f858b00e	169	//
	170	// Returns event_time value as estimated by TOF combinatorial algorithm
	171	//
	172
	173	Int_t ibin = GetMomBin(mom);
	174	return GetT0bin(ibin);
	175
	176	}
	177	//_________________________________________________________________________
7170298c	178	Float_t AliTOFPIDResponse::GetStartTimeRes(Float_t mom) const {
f858b00e	179	//
	180	// Returns event_time resolution as estimated by TOF combinatorial algorithm
	181	//
	182
	183	Int_t ibin = GetMomBin(mom);
	184	return GetT0binRes(ibin);
	185
	186	}
d4d15b21	187	//_________________________________________________________________________
	188	Int_t AliTOFPIDResponse::GetStartTimeMask(Float_t mom) const {
	189	//
	190	// Returns event_time mask
	191	//
	192
	193	Int_t ibin = GetMomBin(mom);
	194	return GetT0binMask(ibin);
	195
	196	}