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 **************************************************************************/
16 //-----------------------------------------------------------------
18 // Implementation of the ITS PID class
19 // Very naive one... Should be made better by the detector experts...
20 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
21 //-----------------------------------------------------------------
22 #include "AliITSpidESD.h"
23 #include "AliITSpidESD1.h"
25 #include "AliESDtrack.h"
27 ClassImp(AliITSpidESD1)
29 AliITSpidESD1::AliITSpidESD1(): AliITSpidESD() {
35 //_________________________________________________________________________
36 AliITSpidESD1::AliITSpidESD1(Double_t *param): AliITSpidESD()
39 // The main constructor
47 //_________________________________________________________________________
48 Int_t AliITSpidESD1::MakePID(AliESD *event)
51 // This function calculates the "detector response" PID probabilities
53 Int_t ntrk=event->GetNumberOfTracks();
54 for (Int_t i=0; i<ntrk; i++) {
55 AliESDtrack *t=event->GetTrack(i);
56 if ((t->GetStatus()&AliESDtrack::kITSin )==0)
57 if ((t->GetStatus()&AliESDtrack::kITSout)==0) continue;
58 Double_t mom=t->GetP();
59 Double_t dedx=t->GetITSsignal()/fMIP;
60 Int_t ns=AliPID::kSPECIES;
62 for (Int_t j=0; j<ns; j++) {
63 Double_t mass=AliPID::ParticleMass(j);
64 Double_t bethe=AliITSpidESD::Bethe(mom/mass);
65 Double_t sigma=fRes*bethe;
66 if (TMath::Abs(dedx-bethe) > fRange*sigma) {
67 p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
70 p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma;