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4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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12 * about the suitability of this software for any purpose. It is *
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14 **************************************************************************/
18 //-----------------------------------------------------------------
19 // Implementation of the combined PID class
20 // For the Event Summary Data Class
21 // produced by the reconstruction process
22 // and containing information on the particle identification
23 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
24 //-----------------------------------------------------------------
32 #include "AliTOFHeader.h"
33 #include "AliESDpid.h"
34 #include "AliESDEvent.h"
35 #include "AliESDtrack.h"
36 #include "AliMCEvent.h"
41 Int_t AliESDpid::MakePID(AliESDEvent *event, Bool_t TPConly, Float_t timeZeroTOF) const {
43 // Calculate probabilities for all detectors, except if TPConly==kTRUE
46 // Option TPConly==kTRUE is used during reconstruction,
47 // because ITS tracking uses TPC pid
48 // HMPID and TRD pid are done in detector reconstructors
52 Float_t timeZeroTOF = 0;
54 timeZeroTOF = event->GetT0();
56 Int_t nTrk=event->GetNumberOfTracks();
57 for (Int_t iTrk=0; iTrk<nTrk; iTrk++) {
58 AliESDtrack *track=event->GetTrack(iTrk);
62 MakeTOFPID(track, timeZeroTOF);
63 //MakeHMPIDPID(track);
70 //_________________________________________________________________________
71 Float_t AliESDpid::GetTPCsignalTunedOnData(const AliVTrack *t) const {
72 AliESDtrack *track = (AliESDtrack *) t;
73 Float_t dedx = track->GetTPCsignalTunedOnData();
75 if(dedx > 0) return dedx;
77 Double_t mom = t->GetTPCmomentum();
78 dedx = t->GetTPCsignal();
79 track->SetTPCsignalTunedOnData(dedx);
80 if(dedx < 20) return dedx;
82 AliPID::EParticleType type = AliPID::kPion;
84 AliMCEventHandler* eventHandler=dynamic_cast<AliMCEventHandler*>(fEventHandler);
86 AliMCEvent* mcEvent = eventHandler->MCEvent();
89 AliMCParticle *MCpart = (AliMCParticle *) mcEvent->GetTrack(TMath::Abs(t->GetLabel()));
90 TParticle *part = MCpart->Particle();
92 Int_t iS = TMath::Abs(part->GetPdgCode());
94 if(iS==AliPID::ParticleCode(AliPID::kElectron)){
95 type = AliPID::kElectron;
97 else if(iS==AliPID::ParticleCode(AliPID::kMuon)){
100 else if(iS==AliPID::ParticleCode(AliPID::kPion)){
101 type = AliPID::kPion;
103 else if(iS==AliPID::ParticleCode(AliPID::kKaon)){
104 type = AliPID::kKaon;
106 else if(iS==AliPID::ParticleCode(AliPID::kProton)){
107 type = AliPID::kProton;
109 else if(iS==AliPID::ParticleCode(AliPID::kDeuteron)){ // d
110 type = AliPID::kDeuteron;
112 else if(iS==AliPID::ParticleCode(AliPID::kTriton)){ // t
113 type = AliPID::kTriton;
115 else if(iS==AliPID::ParticleCode(AliPID::kHe3)){ // 3He
118 else if(iS==AliPID::ParticleCode(AliPID::kAlpha)){ // 4He
119 type = AliPID::kAlpha;
125 Double_t bethe=fTPCResponse.GetExpectedSignal(mom,type);
126 Double_t sigma=fTPCResponse.GetExpectedSigma(mom,t->GetTPCsignalN(),type);
127 dedx = gRandom->Gaus(bethe,sigma);
128 if(iS == AliPID::ParticleCode(AliPID::kHe3) || iS == AliPID::ParticleCode(AliPID::kAlpha)) dedx *= 5;
133 track->SetTPCsignalTunedOnData(dedx);
136 //_________________________________________________________________________
137 void AliESDpid::MakeTPCPID(AliESDtrack *track) const
140 // TPC pid using bethe-bloch and gaussian response
142 if ((track->GetStatus()&AliESDtrack::kTPCin )==0)
143 if ((track->GetStatus()&AliESDtrack::kTPCout)==0) return;
145 Double_t mom = track->GetP();
146 const AliExternalTrackParam *in=track->GetInnerParam();
147 if (in) mom = in->GetP();
149 Double_t p[AliPID::kSPECIES];
150 Double_t dedx=track->GetTPCsignal();
151 Bool_t mismatch=kTRUE, heavy=kTRUE;
153 for (Int_t j=0; j<AliPID::kSPECIES; j++) {
154 AliPID::EParticleType type=AliPID::EParticleType(j);
155 Double_t bethe=fTPCResponse.GetExpectedSignal(mom,type);
156 Double_t sigma=fTPCResponse.GetExpectedSigma(mom,track->GetTPCsignalN(),type);
157 if (TMath::Abs(dedx-bethe) > fRange*sigma) {
158 p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
160 p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma;
164 // Check for particles heavier than (AliPID::kSPECIES - 1)
165 if (dedx < (bethe + fRange*sigma)) heavy=kFALSE;
170 for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1./AliPID::kSPECIES;
174 if (heavy) track->ResetStatus(AliESDtrack::kTPCpid);
177 //_________________________________________________________________________
178 void AliESDpid::MakeITSPID(AliESDtrack *track) const
182 // Two options, depending on fITSPIDmethod:
183 // 1) Truncated mean method
184 // 2) Likelihood, using charges measured in all 4 layers and
185 // Landau+gaus response functions
188 if ((track->GetStatus()&AliESDtrack::kITSin)==0 &&
189 (track->GetStatus()&AliESDtrack::kITSout)==0) return;
191 Double_t mom=track->GetP();
192 if (fITSPIDmethod == kITSTruncMean) {
193 Double_t dedx=track->GetITSsignal();
196 ULong_t trStatus=track->GetStatus();
197 if(trStatus&AliESDtrack::kTPCin) isSA=kFALSE;
198 UChar_t clumap=track->GetITSClusterMap();
199 Int_t nPointsForPid=0;
200 for(Int_t i=2; i<6; i++){
201 if(clumap&(1<<i)) ++nPointsForPid;
204 if(nPointsForPid<3) { // track not to be used for combined PID purposes
205 track->ResetStatus(AliESDtrack::kITSpid);
211 Bool_t mismatch=kTRUE, heavy=kTRUE;
212 for (Int_t j=0; j<AliPID::kSPECIES; j++) {
213 Double_t mass=AliPID::ParticleMass(j);//GeV/c^2
214 Double_t bethe=fITSResponse.Bethe(momITS,mass);
215 Double_t sigma=fITSResponse.GetResolution(bethe,nPointsForPid,isSA);
216 if (TMath::Abs(dedx-bethe) > fRange*sigma) {
217 p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
219 p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma;
223 // Check for particles heavier than (AliPID::kSPECIES - 1)
224 if (dedx < (bethe + fRange*sigma)) heavy=kFALSE;
229 for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1./AliPID::kSPECIES;
233 if (heavy) track->ResetStatus(AliESDtrack::kITSpid);
235 else { // Likelihood method
236 Double_t condprobfun[AliPID::kSPECIES];
238 track->GetITSdEdxSamples(qclu);
239 fITSResponse.GetITSProbabilities(mom,qclu,condprobfun);
240 track->SetITSpid(condprobfun);
244 //_________________________________________________________________________
245 void AliESDpid::MakeTOFPID(AliESDtrack *track, Float_t /*timeZeroTOF*/) const
248 // TOF PID using gaussian response
251 if ((track->GetStatus()&AliESDtrack::kTOFout)==0) return;
252 if ((track->GetStatus()&AliESDtrack::kTIME)==0) return;
253 if ((track->GetStatus()&AliESDtrack::kITSin)==0) return;
255 Int_t ibin = fTOFResponse.GetMomBin(track->GetP());
256 Float_t timezero = fTOFResponse.GetT0bin(ibin);
258 Double_t time[AliPID::kSPECIESN];
259 track->GetIntegratedTimes(time);
261 Double_t sigma[AliPID::kSPECIES];
262 for (Int_t iPart = 0; iPart < AliPID::kSPECIES; iPart++) {
263 sigma[iPart] = fTOFResponse.GetExpectedSigma(track->GetP(),time[iPart],AliPID::ParticleMass(iPart));
266 AliDebugGeneral("AliESDpid::MakeTOFPID",2,
267 Form("Expected TOF signals [ps]: %f %f %f %f %f",
268 time[AliPID::kElectron],
272 time[AliPID::kProton]));
274 AliDebugGeneral("AliESDpid::MakeTOFPID",2,
275 Form("Expected TOF std deviations [ps]: %f %f %f %f %f",
276 sigma[AliPID::kElectron],
277 sigma[AliPID::kMuon],
278 sigma[AliPID::kPion],
279 sigma[AliPID::kKaon],
280 sigma[AliPID::kProton]
283 Double_t tof = track->GetTOFsignal() - timezero;
285 Double_t p[AliPID::kSPECIES];
286 Bool_t mismatch = kTRUE, heavy = kTRUE;
287 for (Int_t j=0; j<AliPID::kSPECIES; j++) {
288 Double_t sig = sigma[j];
289 if (TMath::Abs(tof-time[j]) > (fRange+2)*sig) {
290 p[j] = TMath::Exp(-0.5*(fRange+2)*(fRange+2))/sig;
292 p[j] = TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sig*sig))/sig;
294 // Check the mismatching
296 Double_t mass = AliPID::ParticleMass(j);
297 Double_t pm = fTOFResponse.GetMismatchProbability(track->GetP(),mass);
298 if (p[j]>pm) mismatch = kFALSE;
300 // Check for particles heavier than (AliPID::kSPECIES - 1)
301 if (tof < (time[j] + fRange*sig)) heavy=kFALSE;
307 for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1./AliPID::kSPECIES;
312 if (heavy) track->ResetStatus(AliESDtrack::kTOFpid);
314 if (!CheckTOFMatching(track)) track->SetStatus(AliESDtrack::kTOFmismatch);
315 else track->ResetStatus(AliESDtrack::kTOFmismatch);
317 //_________________________________________________________________________
318 void AliESDpid::MakeTRDPID(AliESDtrack *track) const
321 // Method to recalculate the TRD PID probabilities
323 Double_t prob[AliPID::kSPECIES];
324 ComputeTRDProbability(track, AliPID::kSPECIES, prob);
325 track->SetTRDpid(prob);
327 //_________________________________________________________________________
328 void AliESDpid::CombinePID(AliESDtrack *track) const
331 // Combine the information of various detectors
332 // to determine the Particle Identification
334 Int_t ns=AliPID::kSPECIES;
335 Double_t p[10]={1.,1.,1.,1.,1.,1.,1.,1.,1.,1.};
337 if (track->IsOn(AliESDtrack::kITSpid)) {
340 for (Int_t j=0; j<ns; j++) p[j]*=d[j];
343 if (track->IsOn(AliESDtrack::kTPCpid)) {
346 for (Int_t j=0; j<ns; j++) p[j]*=d[j];
349 if (track->IsOn(AliESDtrack::kTRDpid)) {
352 for (Int_t j=0; j<ns; j++) p[j]*=d[j];
355 if (track->IsOn(AliESDtrack::kTOFpid)) {
358 for (Int_t j=0; j<ns; j++) p[j]*=d[j];
361 if (track->IsOn(AliESDtrack::kHMPIDpid)) {
363 track->GetHMPIDpid(d);
364 for (Int_t j=0; j<ns; j++) p[j]*=d[j];
369 //_________________________________________________________________________
370 Bool_t AliESDpid::CheckTOFMatching(AliESDtrack *track) const{
372 // Check pid matching of TOF with TPC as reference
374 Bool_t status = kFALSE;
376 Double_t exptimes[5];
377 track->GetIntegratedTimes(exptimes);
379 Float_t p = track->P();
381 Float_t dedx = track->GetTPCsignal();
382 Float_t time = track->GetTOFsignal() - fTOFResponse.GetStartTime(p);
385 track->GetInnerPxPyPz(ptpc);
386 Float_t momtpc=TMath::Sqrt(ptpc[0]*ptpc[0] + ptpc[1]*ptpc[1] + ptpc[2]*ptpc[2]);
388 for(Int_t i=0;i < 5;i++){
389 AliPID::EParticleType type=AliPID::EParticleType(i);
391 Float_t resolutionTOF = fTOFResponse.GetExpectedSigma(p, exptimes[i], AliPID::ParticleMass(i));
392 if(TMath::Abs(exptimes[i] - time) < fRange * resolutionTOF){
393 Float_t dedxExp = fTPCResponse.GetExpectedSignal(momtpc,type);
394 Float_t resolutionTPC = fTPCResponse.GetExpectedSigma(momtpc,track->GetTPCsignalN(),type);
396 if(TMath::Abs(dedx - dedxExp) < fRangeTOFMismatch * resolutionTPC){
403 Float_t resolutionTOFpr = fTOFResponse.GetExpectedSigma(p, exptimes[4], AliPID::ParticleMass(4));
404 if(!status && (exptimes[4] + fRange*resolutionTOFpr < time)) status = kTRUE;