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8c6a71ab | 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 | ||
4f679a16 | 16 | /* $Id$ */ |
17 | ||
8c6a71ab | 18 | //----------------------------------------------------------------- |
19 | // Implementation of the combined PID class | |
4f679a16 | 20 | // For the Event Summary Data Class |
21 | // produced by the reconstruction process | |
22 | // and containing information on the particle identification | |
8c6a71ab | 23 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch |
24 | //----------------------------------------------------------------- | |
25 | ||
10d100d4 | 26 | #include "AliLog.h" |
27 | #include "AliPID.h" | |
8c6a71ab | 28 | #include "AliESDpid.h" |
af885e0f | 29 | #include "AliESDEvent.h" |
8c6a71ab | 30 | #include "AliESDtrack.h" |
31 | ||
32 | ClassImp(AliESDpid) | |
33 | ||
10d100d4 | 34 | Int_t AliESDpid::MakePID(AliESDEvent *event, Bool_t TPConly, Float_t TimeZeroTOF) const { |
35 | // | |
36 | // Calculate probabilities for all detectors, except if TPConly==kTRUE | |
37 | // and combine PID | |
38 | // | |
39 | // Option TPConly==kTRUE is used during reconstruction, | |
40 | // because ITS tracking uses TPC pid | |
41 | // HMPID and TRD pid are done in detector reconstructors | |
42 | // | |
43 | ||
44 | /* | |
45 | Float_t TimeZeroTOF = 0; | |
46 | if (subtractT0) | |
47 | TimeZeroTOF = event->GetT0(); | |
48 | */ | |
49 | Int_t nTrk=event->GetNumberOfTracks(); | |
50 | for (Int_t iTrk=0; iTrk<nTrk; iTrk++) { | |
51 | AliESDtrack *track=event->GetTrack(iTrk); | |
52 | MakeTPCPID(track); | |
53 | if (!TPConly) { | |
54 | MakeITSPID(track); | |
55 | MakeTOFPID(track, TimeZeroTOF); | |
56 | //MakeHMPIDPID(track); | |
ce5d6908 | 57 | //MakeTRDPID(track); |
10d100d4 | 58 | } |
59 | CombinePID(track); | |
60 | } | |
61 | return 0; | |
62 | } | |
8c6a71ab | 63 | //_________________________________________________________________________ |
10d100d4 | 64 | void AliESDpid::MakeTPCPID(AliESDtrack *track) const |
8c6a71ab | 65 | { |
4f679a16 | 66 | // |
10d100d4 | 67 | // TPC pid using bethe-bloch and gaussian response |
4f679a16 | 68 | // |
10d100d4 | 69 | if ((track->GetStatus()&AliESDtrack::kTPCin )==0) |
70 | if ((track->GetStatus()&AliESDtrack::kTPCout)==0) return; | |
8c6a71ab | 71 | |
10d100d4 | 72 | Double_t mom = track->GetP(); |
73 | const AliExternalTrackParam *in=track->GetInnerParam(); | |
74 | if (in) mom = in->GetP(); | |
8c6a71ab | 75 | |
10d100d4 | 76 | Double_t p[AliPID::kSPECIES]; |
77 | Double_t dedx=track->GetTPCsignal(); | |
78 | Bool_t mismatch=kTRUE, heavy=kTRUE; | |
8c6a71ab | 79 | |
10d100d4 | 80 | for (Int_t j=0; j<AliPID::kSPECIES; j++) { |
81 | AliPID::EParticleType type=AliPID::EParticleType(j); | |
82 | Double_t bethe=fTPCResponse.GetExpectedSignal(mom,type); | |
83 | Double_t sigma=fTPCResponse.GetExpectedSigma(mom,track->GetTPCsignalN(),type); | |
84 | if (TMath::Abs(dedx-bethe) > fRange*sigma) { | |
85 | p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma; | |
86 | } else { | |
87 | p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma; | |
88 | mismatch=kFALSE; | |
89 | } | |
8c6a71ab | 90 | |
10d100d4 | 91 | // Check for particles heavier than (AliPID::kSPECIES - 1) |
92 | if (dedx < (bethe + fRange*sigma)) heavy=kFALSE; | |
c630aafd | 93 | |
4a78b8c5 | 94 | } |
95 | ||
10d100d4 | 96 | if (mismatch) |
97 | for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES; | |
98 | ||
99 | track->SetTPCpid(p); | |
100 | ||
101 | if (heavy) track->ResetStatus(AliESDtrack::kTPCpid); | |
102 | ||
103 | } | |
104 | //_________________________________________________________________________ | |
105 | void AliESDpid::MakeITSPID(AliESDtrack *track) const | |
106 | { | |
107 | // | |
108 | // ITS PID | |
109 | // Two options, depending on fITSPIDmethod: | |
110 | // 1) Truncated mean method | |
111 | // 2) Likelihood, using charges measured in all 4 layers and | |
112 | // Landau+gaus response functions | |
113 | // | |
114 | ||
115 | if ((track->GetStatus()&AliESDtrack::kITSin)==0 && | |
116 | (track->GetStatus()&AliESDtrack::kITSout)==0) return; | |
117 | ||
118 | Double_t mom=track->GetP(); | |
119 | if (fITSPIDmethod == kITSTruncMean) { | |
120 | Double_t dedx=track->GetITSsignal(); | |
15e979c9 | 121 | Bool_t isSA=kTRUE; |
122 | Double_t momITS=mom; | |
123 | ULong_t trStatus=track->GetStatus(); | |
99daa709 | 124 | if(trStatus&AliESDtrack::kTPCin) isSA=kFALSE; |
15e979c9 | 125 | UChar_t clumap=track->GetITSClusterMap(); |
126 | Int_t nPointsForPid=0; | |
127 | for(Int_t i=2; i<6; i++){ | |
128 | if(clumap&(1<<i)) ++nPointsForPid; | |
129 | } | |
130 | ||
131 | if(nPointsForPid<3) { // track not to be used for combined PID purposes | |
132 | track->ResetStatus(AliESDtrack::kITSpid); | |
133 | return; | |
134 | } | |
135 | ||
10d100d4 | 136 | Double_t p[10]; |
15e979c9 | 137 | |
10d100d4 | 138 | Bool_t mismatch=kTRUE, heavy=kTRUE; |
139 | for (Int_t j=0; j<AliPID::kSPECIES; j++) { | |
140 | Double_t mass=AliPID::ParticleMass(j);//GeV/c^2 | |
15e979c9 | 141 | Double_t bethe=fITSResponse.Bethe(momITS,mass); |
142 | Double_t sigma=fITSResponse.GetResolution(bethe,nPointsForPid,isSA); | |
10d100d4 | 143 | if (TMath::Abs(dedx-bethe) > fRange*sigma) { |
144 | p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma; | |
145 | } else { | |
146 | p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma; | |
147 | mismatch=kFALSE; | |
148 | } | |
149 | ||
150 | // Check for particles heavier than (AliPID::kSPECIES - 1) | |
151 | if (dedx < (bethe + fRange*sigma)) heavy=kFALSE; | |
152 | ||
4a78b8c5 | 153 | } |
c630aafd | 154 | |
10d100d4 | 155 | if (mismatch) |
156 | for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1./AliPID::kSPECIES; | |
157 | ||
158 | track->SetITSpid(p); | |
159 | ||
160 | if (heavy) track->ResetStatus(AliESDtrack::kITSpid); | |
161 | } | |
162 | else { // Likelihood method | |
163 | Double_t condprobfun[AliPID::kSPECIES]; | |
164 | Double_t qclu[4]; | |
165 | track->GetITSdEdxSamples(qclu); | |
166 | fITSResponse.GetITSProbabilities(mom,qclu,condprobfun); | |
167 | track->SetITSpid(condprobfun); | |
8c6a71ab | 168 | } |
7a8614f3 | 169 | |
10d100d4 | 170 | } |
171 | //_________________________________________________________________________ | |
172 | void AliESDpid::MakeTOFPID(AliESDtrack *track, Float_t TimeZeroTOF) const | |
173 | { | |
174 | // | |
175 | // TOF PID using gaussian response | |
176 | // | |
177 | if ((track->GetStatus()&AliESDtrack::kTOFout)==0) return; | |
178 | if ((track->GetStatus()&AliESDtrack::kTIME)==0) return; | |
179 | ||
180 | Double_t time[AliPID::kSPECIESN]; | |
181 | track->GetIntegratedTimes(time); | |
182 | ||
183 | Double_t sigma[AliPID::kSPECIES]; | |
184 | for (Int_t iPart = 0; iPart < AliPID::kSPECIES; iPart++) { | |
185 | sigma[iPart] = fTOFResponse.GetExpectedSigma(track->GetP(),time[iPart],AliPID::ParticleMass(iPart)); | |
186 | } | |
187 | ||
188 | AliDebugGeneral("AliESDpid::MakeTOFPID",2, | |
189 | Form("Expected TOF signals [ps]: %f %f %f %f %f", | |
190 | time[AliPID::kElectron], | |
191 | time[AliPID::kMuon], | |
192 | time[AliPID::kPion], | |
193 | time[AliPID::kKaon], | |
194 | time[AliPID::kProton])); | |
195 | ||
196 | AliDebugGeneral("AliESDpid::MakeTOFPID",2, | |
197 | Form("Expected TOF std deviations [ps]: %f %f %f %f %f", | |
198 | sigma[AliPID::kElectron], | |
199 | sigma[AliPID::kMuon], | |
200 | sigma[AliPID::kPion], | |
201 | sigma[AliPID::kKaon], | |
202 | sigma[AliPID::kProton] | |
203 | )); | |
204 | ||
205 | Double_t tof = track->GetTOFsignal() - TimeZeroTOF; | |
206 | ||
207 | Double_t p[AliPID::kSPECIES]; | |
208 | Bool_t mismatch = kTRUE, heavy = kTRUE; | |
209 | for (Int_t j=0; j<AliPID::kSPECIES; j++) { | |
210 | Double_t sig = sigma[j]; | |
211 | if (TMath::Abs(tof-time[j]) > fRange*sig) { | |
212 | p[j] = TMath::Exp(-0.5*fRange*fRange)/sig; | |
213 | } else | |
214 | p[j] = TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sig*sig))/sig; | |
215 | ||
216 | // Check the mismatching | |
217 | Double_t mass = AliPID::ParticleMass(j); | |
218 | Double_t pm = fTOFResponse.GetMismatchProbability(track->GetP(),mass); | |
219 | if (p[j]>pm) mismatch = kFALSE; | |
220 | ||
221 | // Check for particles heavier than (AliPID::kSPECIES - 1) | |
222 | if (tof < (time[j] + fRange*sig)) heavy=kFALSE; | |
223 | ||
224 | } | |
225 | ||
226 | if (mismatch) | |
227 | for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES; | |
228 | ||
229 | track->SetTOFpid(p); | |
230 | ||
231 | if (heavy) track->ResetStatus(AliESDtrack::kTOFpid); | |
232 | } | |
233 | //_________________________________________________________________________ | |
b439f460 | 234 | void AliESDpid::MakeTRDPID(AliESDtrack *track) const |
235 | { | |
236 | // | |
237 | // Method to recalculate the TRD PID probabilities | |
238 | // | |
239 | if((track->GetStatus()&AliESDtrack::kTRDout)==0) return; | |
240 | Double_t prob[AliPID::kSPECIES]; Float_t mom[6]; | |
241 | Double_t dedx[48]; // Allocate space for the maximum number of TRD slices | |
242 | for(Int_t ilayer = 0; ilayer < 6; ilayer++){ | |
243 | mom[ilayer] = track->GetTRDmomentum(ilayer); | |
244 | for(Int_t islice = 0; islice < track->GetNumberOfTRDslices(); islice++){ | |
245 | dedx[ilayer*track->GetNumberOfTRDslices()+islice] = track->GetTRDslice(ilayer, islice); | |
246 | } | |
247 | } | |
248 | fTRDResponse.GetResponse(track->GetNumberOfTRDslices(), dedx, mom, prob); | |
249 | track->SetTRDpid(prob); | |
250 | } | |
251 | //_________________________________________________________________________ | |
10d100d4 | 252 | void AliESDpid::CombinePID(AliESDtrack *track) const |
253 | { | |
254 | // | |
255 | // Combine the information of various detectors | |
256 | // to determine the Particle Identification | |
257 | // | |
258 | Int_t ns=AliPID::kSPECIES; | |
259 | Double_t p[10]={1.,1.,1.,1.,1.,1.,1.,1.,1.,1.}; | |
260 | ||
261 | if (track->IsOn(AliESDtrack::kITSpid)) { | |
262 | Double_t d[10]; | |
263 | track->GetITSpid(d); | |
264 | for (Int_t j=0; j<ns; j++) p[j]*=d[j]; | |
265 | } | |
266 | ||
267 | if (track->IsOn(AliESDtrack::kTPCpid)) { | |
268 | Double_t d[10]; | |
269 | track->GetTPCpid(d); | |
270 | for (Int_t j=0; j<ns; j++) p[j]*=d[j]; | |
271 | } | |
272 | ||
273 | if (track->IsOn(AliESDtrack::kTRDpid)) { | |
274 | Double_t d[10]; | |
275 | track->GetTRDpid(d); | |
276 | for (Int_t j=0; j<ns; j++) p[j]*=d[j]; | |
277 | } | |
278 | ||
279 | if (track->IsOn(AliESDtrack::kTOFpid)) { | |
280 | Double_t d[10]; | |
281 | track->GetTOFpid(d); | |
282 | for (Int_t j=0; j<ns; j++) p[j]*=d[j]; | |
283 | } | |
284 | ||
285 | if (track->IsOn(AliESDtrack::kHMPIDpid)) { | |
286 | Double_t d[10]; | |
287 | track->GetHMPIDpid(d); | |
288 | for (Int_t j=0; j<ns; j++) p[j]*=d[j]; | |
289 | } | |
290 | ||
291 | track->SetESDpid(p); | |
8c6a71ab | 292 | } |