[u/mrichter/AliRoot.git] / STEER / AliTOFpidESD.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 "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;
}
Commit	Line	Data
b9d9108c	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 "AliESDtrack.h"
	27	#include "AliESDEvent.h"
	28
	29	#include "AliTOFpidESD.h"
	30
	31	ClassImp(AliTOFpidESD)
	32
	33	//_________________________________________________________________________
	34	AliTOFpidESD::AliTOFpidESD():
	35	fSigma(0),
	36	fRange(0),
	37	fPmax(0), // zero at 0.5 GeV/c for pp
	38	fTime0(0)
	39	{
	40	}
	41	//_________________________________________________________________________
	42	AliTOFpidESD::AliTOFpidESD(Double_t *param):
	43	fSigma(param[0]),
	44	fRange(param[1]),
	45	fPmax(0), // zero at 0.5 GeV/c for pp
	46	fTime0(0)
	47	{
	48	//
	49	// The main constructor
	50	//
	51	//
	52
	53	//fPmax=TMath::Exp(-0.533)/fSigma; // ~3 sigma at 0.5 GeV/c for PbPb
	54	}
	55
	56	//_________________________________________________________________________
	57	Double_t
	58	AliTOFpidESD::GetMismatchProbability(Double_t p, Double_t mass) const {
	59	//
	60	// Returns the probability of mismatching
	61	// assuming 1/(p*beta)^2 scaling
	62	//
	63	const Double_t km=0.5; // "reference" momentum (GeV/c)
	64
65	Double_t ref2=kmkmkmkm/(kmkm + massmass);// "reference" (pbeta)^2
66	Double_t p2beta2=pppp/(pp + mass*mass);
67
68	return fPmax*ref2/p2beta2;
69	}
70
71	//_________________________________________________________________________
72	Int_t AliTOFpidESD::MakePID(AliESDEvent *event, Double_t timeZero)
73	{
74	//
75	// This function calculates the "detector response" PID probabilities
76	// Just for a bare hint...
77
78	AliDebug(1,Form("TOF PID Parameters: Sigma (ps)= %f, Range= %f",fSigma,fRange));
79	AliDebug(1,"++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ \n");
80
81	fTime0=timeZero;
82	return MakePID(event);
83	}
84
85	//_________________________________________________________________________
86	Int_t AliTOFpidESD::MakePID(AliESDEvent *event)
87	{
88	//
89	// This function calculates the "detector response" PID probabilities
90	// Just for a bare hint...
91
92	Int_t ntrk=event->GetNumberOfTracks();
93	AliESDtrack *tracks=new AliESDtrack[ntrk];
94
95	Int_t i;
96	for (i=0; i<ntrk; i++) {
97	AliESDtrack *t=event->GetTrack(i);
98	tracks[i]=t;
99	}
100
101	for (i=0; i<ntrk; i++) {
102	AliESDtrack *t=tracks[i];
103	if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue;
104	if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue;
105
106	Double_t time[AliPID::kSPECIES];
107	if (!ExpectedSignals(t,time,AliPID::kSPECIES)) continue;
108	Double_t sigma[AliPID::kSPECIES];
109	if (!ExpectedSigmas(t,sigma,AliPID::kSPECIES)) continue;
110
111	AliDebug(2,Form("Expected TOF signals [ps]: %f %f %f %f %f",
112	GetExpectedSignal(t,AliPID::kElectron),
113	GetExpectedSignal(t,AliPID::kMuon),
114	GetExpectedSignal(t,AliPID::kPion),
115	GetExpectedSignal(t,AliPID::kKaon),
116	GetExpectedSignal(t,AliPID::kProton)
117	));
118
119	AliDebug(2,Form("Expected TOF std deviations [ps]: %f %f %f %f %f",
120	GetExpectedSigma(t,AliPID::kElectron),
121	GetExpectedSigma(t,AliPID::kMuon),
122	GetExpectedSigma(t,AliPID::kPion),
123	GetExpectedSigma(t,AliPID::kKaon),
124	GetExpectedSigma(t,AliPID::kProton)
125	));
126
127	AliDebug(2,Form("Expected TOF std deviations [number of expected sigmas]: %f %f %f %f %f",
128	GetNumberOfSigmas(t,AliPID::kElectron),
129	GetNumberOfSigmas(t,AliPID::kMuon),
130	GetNumberOfSigmas(t,AliPID::kPion),
131	GetNumberOfSigmas(t,AliPID::kKaon),
132	GetNumberOfSigmas(t,AliPID::kProton)
133	));
134
135	Double_t tof = t->GetTOFsignal() - fTime0;
136
137	Double_t p[AliPID::kSPECIES];
138	Bool_t mismatch = kTRUE, heavy = kTRUE;
139	for (Int_t j=0; j<AliPID::kSPECIES; j++) {
140	Double_t sig = sigma[j];
141	if (TMath::Abs(tof-time[j]) > fRange*sig) {
142	p[j] = TMath::Exp(-0.5fRangefRange)/sig;
143	} else
144	p[j] = TMath::Exp(-0.5(tof-time[j])(tof-time[j])/(sig*sig))/sig;
145
146	// Check the mismatching
147	Double_t mass = AliPID::ParticleMass(j);
148	Double_t pm = GetMismatchProbability(t->GetP(),mass);
149	if (p[j]>pm) mismatch = kFALSE;
150
151	// Check for particles heavier than (AliPID::kSPECIES - 1)
152	if (tof < (time[j] + fRange*sig)) heavy=kFALSE;
153
154	}
155
156	if (mismatch)
157	for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES;
158
159	t->SetTOFpid(p);
160
161	if (heavy) t->ResetStatus(AliESDtrack::kTOFpid);
162
163	}
164
165	delete[] tracks;
166
167	return 0;
168	}
169
170	//_________________________________________________________________________
171	Bool_t AliTOFpidESD::ExpectedSignals(const AliESDtrack *t,
172	Double_t s[],Int_t n) const
173	{
174	//
175	// Return the expected PID signals for the involved particle species
176	//
177
178	if (n > AliPID::kSPECIESN) return kFALSE;
179	if ( !t->IsOn(AliESDtrack::kTIME) ) return kFALSE;
180
181	Double_t time[AliPID::kSPECIESN];
182	t->GetIntegratedTimes(time);
183	for (Int_t i=0; i<n; i++) s[i]=time[i];
184	return kTRUE;
185	}
186
187	//_________________________________________________________________________
188	Bool_t AliTOFpidESD::ExpectedSigmas(const AliESDtrack *t,
189	Double_t s[],Int_t n) const
190	{
191	//
192	// Return the expected sigma of PID signals for the involved
193	// particle species.
194	// This approximate (but reasonable) formula takes into account the
195	// relative momentum resolution.
196	//
197
198	Double_t time[AliPID::kSPECIESN];
199	if ( !ExpectedSignals(t,time,n) ) return kFALSE;
200
201	Double_t mom = t->GetP();
202	Double_t dpp = 0.01; //mean relative pt resolution;
203	if (mom>0.5) dpp = 0.01*mom;
204	for (Int_t i=0; i<n; i++) {
205	Double_t mass = AliPID::ParticleMass(i);
206	Double_t sigma = dpptime[i]/(1.+ mommom/(mass*mass));
207	s[i] = TMath::Sqrt(sigmasigma + fSigmafSigma);
208	}
209	return kTRUE;
210	}
211
212	//_________________________________________________________________________
213	Bool_t AliTOFpidESD::NumberOfSigmas(const AliESDtrack *t,
214	Double_t s[],Int_t n) const
215	{
216	//
217	// Returns the deviation of the actual PID signal from the expected
218	// signal, in units of expected sigmas.
219	//
220
221	Double_t time[AliPID::kSPECIESN];
222	if ( !ExpectedSignals(t,time,n) ) return kFALSE;
223
224	if ( !ExpectedSigmas(t,s,n) ) return kFALSE;
225
226	Double_t tof = t->GetTOFsignal() - fTime0;
227	for (Int_t i=0; i<n; i++) s[i] = (time[i]-tof)/s[i];
228
229	return kTRUE;
230	}
231
232	//_________________________________________________________________________
233	Double_t AliTOFpidESD::GetExpectedSignal(const AliESDtrack *t,
234	AliPID::EParticleType n) const
235	{
236	//
237	// Return the expected PID signal for the specified particle type.
238	// If the operation is not possible, return a negative value.
239	//
240
241	if (Int_t(n) >= AliPID::kSPECIESN) return -1.;
242	if ( !t->IsOn(AliESDtrack::kTIME) ) return -1.;
243
244	Double_t time[AliPID::kSPECIESN];
245	t->GetIntegratedTimes(time);
246
247	return time[n];
248	}
249
250	//_________________________________________________________________________
251	Double_t AliTOFpidESD::GetExpectedSigma(const AliESDtrack *t,
252	AliPID::EParticleType n) const
253	{
254	//
255	// Return the expected sigma of the PID signal for the specified
256	// particle type.
257	// If the operation is not possible, return a negative value.
258	//
259
260	Double_t time[AliPID::kSPECIESN];
261	if ( !ExpectedSignals(t,time,AliPID::kSPECIESN) ) return -1.;
262
263	Double_t mom = t->GetP();
264	Double_t dpp = 0.01; //mean relative pt resolution;
265	if (mom>0.5) dpp = 0.01*mom;
266
267	Double_t mass = AliPID::ParticleMass(n);
268	Double_t sigma = dpptime[n]/(1.+ mommom/(mass*mass));
269
270	return TMath::Sqrt(sigmasigma + fSigmafSigma);
271	}
272
273	//_________________________________________________________________________
274	Double_t AliTOFpidESD::GetNumberOfSigmas(const AliESDtrack *t,
275	AliPID::EParticleType n) const
276	{
277	//
278	// Returns the deviation of the actual PID signal from the expected
279	// signal for the specified particle type, in units of expected
280	// sigmas.
281	// If the operation is not possible, return a negative value.
282	//
283
284	Double_t time=GetExpectedSignal(t,n);;
285	if (time < 0.) return -1.;
286
287	Double_t sigma=GetExpectedSigma(t,n);
288	if (sigma < 0.) return -1;
289
290	Double_t tof=t->GetTOFsignal() - fTime0;
291	return (time-tof)/sigma;
292	}