1 /**************************************************************************
2 * Copyright(c) 2005-2007, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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8 * documentation strictly for non-commercial purposes is hereby granted *
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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 **************************************************************************/
18 //-----------------------------------------------------------------
20 // Implementation of the ITS PID class
21 // Very naive one... Should be made better by the detector experts...
22 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
23 //-----------------------------------------------------------------
24 #include "AliITSpidESD.h"
25 #include "AliITSpidESD1.h"
26 #include "AliESDEvent.h"
27 #include "AliESDtrack.h"
29 ClassImp(AliITSpidESD1)
31 AliITSpidESD1::AliITSpidESD1(): AliITSpidESD(),
38 //_________________________________________________________________________
39 AliITSpidESD1::AliITSpidESD1(Double_t *param): AliITSpidESD(),
45 // The main constructor
50 //_________________________________________________________________________
51 Int_t AliITSpidESD1::MakePID(AliESDEvent *event)
54 // This function calculates the "detector response" PID probabilities
56 Int_t ntrk=event->GetNumberOfTracks();
57 for (Int_t i=0; i<ntrk; i++) {
58 AliESDtrack *t=event->GetTrack(i);
59 if ((t->GetStatus()&AliESDtrack::kITSin )==0)
60 if ((t->GetStatus()&AliESDtrack::kITSout)==0) continue;
61 Double_t mom=t->GetP();
62 Double_t dedx=t->GetITSsignal()/fMIP;
64 Bool_t mismatch=kTRUE, heavy=kTRUE;
65 for (Int_t j=0; j<AliPID::kSPECIES; j++) {
66 Double_t mass=AliPID::ParticleMass(j);//GeV/c^2
67 Double_t bethe=AliITSpidESD::Bethe(mom,mass);
68 Double_t sigma=fRes*bethe;
69 if (TMath::Abs(dedx-bethe) > fRange*sigma) {
70 p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
72 p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma;
76 // Check for particles heavier than (AliPID::kSPECIES - 1)
77 if (dedx < (bethe + fRange*sigma)) heavy=kFALSE;
82 for (Int_t j=0; j<AliPID::kSPECIES; j++) p[j]=1/AliPID::kSPECIES;
86 if (heavy) t->ResetStatus(AliESDtrack::kITSpid);