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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 | // Implementation of the TOF PID class | |
18 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch | |
19 | //----------------------------------------------------------------- | |
20 | #include "TError.h" | |
21 | #include "AliTOFpidESD.h" | |
22 | #include "AliESDtrack.h" | |
23 | #include "AliESD.h" | |
24 | ||
25 | ClassImp(AliTOFpidESD) | |
26 | ||
27 | //_________________________________________________________________________ | |
28 | AliTOFpidESD::AliTOFpidESD(Double_t *param) { | |
29 | // | |
30 | // The main constructor | |
31 | // | |
32 | fN=0; fEventN=0; | |
33 | ||
34 | fSigma=param[0]; | |
35 | fRange=param[1]; | |
36 | ||
37 | } | |
38 | ||
39 | //_________________________________________________________________________ | |
40 | Int_t AliTOFpidESD::MakePID(AliESD *event) | |
41 | { | |
42 | // | |
43 | // This function calculates the "detector response" PID probabilities | |
44 | // Just for a bare hint... | |
45 | ||
46 | static const Double_t kMasses[]={ | |
47 | 0.000511, 0.105658, 0.139570, 0.493677, 0.938272, 1.875613 | |
48 | }; | |
49 | ||
50 | Int_t ntrk=event->GetNumberOfTracks(); | |
51 | AliESDtrack **tracks=new AliESDtrack*[ntrk]; | |
52 | ||
53 | Int_t i; | |
54 | for (i=0; i<ntrk; i++) { | |
55 | AliESDtrack *t=event->GetTrack(i); | |
56 | tracks[i]=t; | |
57 | } | |
58 | ||
59 | for (i=0; i<ntrk; i++) { | |
60 | AliESDtrack *t=tracks[i]; | |
61 | if ((t->GetStatus()&AliESDtrack::kTOFout)==0) continue; | |
62 | if ((t->GetStatus()&AliESDtrack::kTIME)==0) continue; | |
63 | Double_t tof=t->GetTOFsignal(); | |
64 | Double_t time[10]; t->GetIntegratedTimes(time); | |
65 | Double_t p[10]; | |
66 | Double_t mom=t->GetP(); | |
67 | for (Int_t j=0; j<AliESDtrack::kSPECIES; j++) { | |
68 | Double_t mass=kMasses[j]; | |
69 | Double_t dpp=0.01; //mean relative pt resolution; | |
70 | if (mom>0.5) dpp=0.01*mom; | |
71 | Double_t sigma=dpp*time[j]/(1.+ mom*mom/(mass*mass)); | |
72 | sigma=TMath::Sqrt(sigma*sigma + fSigma*fSigma); | |
73 | if (TMath::Abs(tof-time[j]) > fRange*sigma) { | |
74 | p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma; | |
75 | continue; | |
76 | } | |
77 | p[j]=TMath::Exp(-0.5*(tof-time[j])*(tof-time[j])/(sigma*sigma))/sigma; | |
78 | } | |
79 | t->SetTOFpid(p); | |
80 | } | |
81 | ||
82 | delete[] tracks; | |
83 | ||
84 | return 0; | |
85 | } | |
86 |