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c630aafd | 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 | ||
0e46b9ae | 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" | |
02cdc6ac | 24 | #include "AliLog.h" |
0e46b9ae | 25 | |
c630aafd | 26 | #include "AliESDtrack.h" |
af885e0f | 27 | #include "AliESDEvent.h" |
c630aafd | 28 | |
0e46b9ae | 29 | #include "AliTOFpidESD.h" |
30 | ||
c630aafd | 31 | ClassImp(AliTOFpidESD) |
32 | ||
0f4a7374 | 33 | //_________________________________________________________________________ |
7a8614f3 | 34 | AliTOFpidESD::AliTOFpidESD(): |
655e379f | 35 | fSigma(0), |
7a8614f3 | 36 | fRange(0), |
37 | fPmax(0) // zero at 0.5 GeV/c for pp | |
655e379f | 38 | { |
39 | } | |
40 | //_________________________________________________________________________ | |
41 | AliTOFpidESD::AliTOFpidESD(Double_t *param): | |
7a8614f3 | 42 | fSigma(param[0]), |
43 | fRange(param[1]), | |
44 | fPmax(0) // zero at 0.5 GeV/c for pp | |
45 | { | |
0f4a7374 | 46 | // |
47 | // The main constructor | |
48 | // | |
7a8614f3 | 49 | // |
50 | ||
51 | //fPmax=TMath::Exp(-0.5*3*3)/fSigma; // ~3 sigma at 0.5 GeV/c for PbPb | |
52 | } | |
53 | ||
54 | Double_t | |
55 | AliTOFpidESD::GetMismatchProbability(Double_t p, Double_t mass) const { | |
56 | // | |
57 | // Returns the probability of mismatching | |
58 | // assuming 1/(p*beta)^2 scaling | |
59 | // | |
60 | const Double_t m=0.5; // "reference" momentum (GeV/c) | |
61 | ||
62 | Double_t ref2=m*m*m*m/(m*m + mass*mass);// "reference" (p*beta)^2 | |
63 | Double_t p2beta2=p*p*p*p/(p*p + mass*mass); | |
0f4a7374 | 64 | |
7a8614f3 | 65 | return fPmax*ref2/p2beta2; |
0f4a7374 | 66 | } |
67 | ||
bc9f08da | 68 | //_________________________________________________________________________ |
af885e0f | 69 | Int_t AliTOFpidESD::MakePID(AliESDEvent *event, Double_t timeZero) |
bc9f08da | 70 | { |
71 | // | |
72 | // This function calculates the "detector response" PID probabilities | |
73 | // Just for a bare hint... | |
74 | ||
02cdc6ac | 75 | AliDebug(1,Form("TOF PID Parameters: Sigma (ps)= %f, Range= %f",fSigma,fRange)); |
76 | AliDebug(1,"++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ \n"); | |
7a8614f3 | 77 | |
bc9f08da | 78 | Int_t ntrk=event->GetNumberOfTracks(); |
79 | AliESDtrack **tracks=new AliESDtrack*[ntrk]; | |
80 | ||
81 | Int_t i; | |
82 | for (i=0; i<ntrk; i++) { | |
83 | AliESDtrack *t=event->GetTrack(i); | |
84 | tracks[i]=t; | |
85 | } | |
86 | ||
87 | for (i=0; i<ntrk; i++) { | |
88 | AliESDtrack *t=tracks[i]; | |
89 | if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue; | |
90 | if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue; | |
91 | Double_t tof=t->GetTOFsignal()-timeZero; | |
92 | Double_t time[10]; t->GetIntegratedTimes(time); | |
93 | Double_t p[10]; | |
94 | Double_t mom=t->GetP(); | |
7a8614f3 | 95 | Bool_t mismatch=kTRUE, heavy=kTRUE; |
bc9f08da | 96 | for (Int_t j=0; j<AliPID::kSPECIES; j++) { |
97 | Double_t mass=AliPID::ParticleMass(j); | |
98 | Double_t dpp=0.01; //mean relative pt resolution; | |
99 | if (mom>0.5) dpp=0.01*mom; | |
100 | Double_t sigma=dpp*time[j]/(1.+ mom*mom/(mass*mass)); | |
101 | sigma=TMath::Sqrt(sigma*sigma + fSigma*fSigma); | |
102 | if (TMath::Abs(tof-time[j]) > fRange*sigma) { | |
103 | p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma; | |
7a8614f3 | 104 | } else |
105 | p[j]=TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sigma*sigma))/sigma; | |
106 | ||
107 | // Check the mismatching | |
108 | Double_t pm=GetMismatchProbability(mom,mass); | |
109 | if (p[j]>pm) mismatch=kFALSE; | |
110 | ||
111 | // Check for particles heavier than (AliPID::kSPECIES - 1) | |
112 | if (tof < (time[j] + fRange*sigma)) heavy=kFALSE; | |
113 | ||
bc9f08da | 114 | } |
7a8614f3 | 115 | |
116 | if (mismatch) | |
117 | for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES; | |
118 | ||
bc9f08da | 119 | t->SetTOFpid(p); |
7a8614f3 | 120 | |
121 | if (heavy) t->ResetStatus(AliESDtrack::kTOFpid); | |
122 | ||
bc9f08da | 123 | } |
124 | ||
125 | delete[] tracks; | |
126 | ||
127 | return 0; | |
128 | } | |
129 | ||
c630aafd | 130 | //_________________________________________________________________________ |
af885e0f | 131 | Int_t AliTOFpidESD::MakePID(AliESDEvent *event) |
c630aafd | 132 | { |
133 | // | |
134 | // This function calculates the "detector response" PID probabilities | |
135 | // Just for a bare hint... | |
136 | ||
c630aafd | 137 | Int_t ntrk=event->GetNumberOfTracks(); |
3f83f224 | 138 | AliESDtrack **tracks=new AliESDtrack*[ntrk]; |
139 | ||
140 | Int_t i; | |
141 | for (i=0; i<ntrk; i++) { | |
c630aafd | 142 | AliESDtrack *t=event->GetTrack(i); |
3f83f224 | 143 | tracks[i]=t; |
144 | } | |
3f83f224 | 145 | |
3f83f224 | 146 | for (i=0; i<ntrk; i++) { |
147 | AliESDtrack *t=tracks[i]; | |
74ea065c | 148 | if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue; |
3f83f224 | 149 | if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue; |
74ea065c | 150 | Double_t tof=t->GetTOFsignal(); |
151 | Double_t time[10]; t->GetIntegratedTimes(time); | |
c630aafd | 152 | Double_t p[10]; |
153 | Double_t mom=t->GetP(); | |
7a8614f3 | 154 | Bool_t mismatch=kTRUE, heavy=kTRUE; |
304864ab | 155 | for (Int_t j=0; j<AliPID::kSPECIES; j++) { |
156 | Double_t mass=AliPID::ParticleMass(j); | |
3f83f224 | 157 | Double_t dpp=0.01; //mean relative pt resolution; |
158 | if (mom>0.5) dpp=0.01*mom; | |
159 | Double_t sigma=dpp*time[j]/(1.+ mom*mom/(mass*mass)); | |
c630aafd | 160 | sigma=TMath::Sqrt(sigma*sigma + fSigma*fSigma); |
161 | if (TMath::Abs(tof-time[j]) > fRange*sigma) { | |
431be10d | 162 | p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma; |
7a8614f3 | 163 | } else |
164 | p[j]=TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sigma*sigma))/sigma; | |
165 | ||
166 | // Check the mismatching | |
167 | Double_t pm=GetMismatchProbability(mom,mass); | |
168 | if (p[j]>pm) mismatch=kFALSE; | |
169 | ||
170 | // Check for particles heavier than (AliPID::kSPECIES - 1) | |
171 | if (tof < (time[j] + fRange*sigma)) heavy=kFALSE; | |
172 | ||
c630aafd | 173 | } |
7a8614f3 | 174 | |
175 | if (mismatch) | |
176 | for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES; | |
177 | ||
c630aafd | 178 | t->SetTOFpid(p); |
7a8614f3 | 179 | |
180 | if (heavy) t->ResetStatus(AliESDtrack::kTOFpid); | |
181 | ||
c630aafd | 182 | } |
183 | ||
3f83f224 | 184 | delete[] tracks; |
74ea065c | 185 | |
c630aafd | 186 | return 0; |
187 | } | |
0f4a7374 | 188 |