Defining properly momentum components in AliMUONHit constructors (thanks Artur)
[u/mrichter/AliRoot.git] / TPC / AliTPCpidESD.cxx
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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. *
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8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
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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 **************************************************************************/
15
16//-----------------------------------------------------------------
17// Implementation of the TPC PID class
18// Very naive one... Should be made better by the detector experts...
19// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
20//-----------------------------------------------------------------
21
22#include "AliTPCpidESD.h"
23#include "AliESD.h"
24#include "AliESDtrack.h"
25
26ClassImp(AliTPCpidESD)
27
28//_________________________________________________________________________
29AliTPCpidESD::AliTPCpidESD(Double_t *param)
30{
31 //
32 // The main constructor
33 //
34 fMIP=param[0];
35 fRes=param[1];
36 fRange=param[2];
37}
38
39Double_t AliTPCpidESD::Bethe(Double_t bg) {
40 //
41 // This is the Bethe-Bloch function normalised to 1 at the minimum
42 //
43 Double_t bg2=bg*bg;
44 Double_t bethe=(1.+ bg2)/bg2*(log(5940*bg2) - bg2/(1.+ bg2));
45 return bethe/11.091;
46}
47
48//_________________________________________________________________________
49Int_t AliTPCpidESD::MakePID(AliESD *event)
50{
51 //
52 // This function calculates the "detector response" PID probabilities
53 //
54 static const Double_t masses[]={
55 0.000511, 0.105658, 0.139570, 0.493677, 0.938272, 1.875613
56 };
57 Int_t ntrk=event->GetNumberOfTracks();
58 for (Int_t i=0; i<ntrk; i++) {
59 AliESDtrack *t=event->GetTrack(i);
60 if ((t->GetStatus()&AliESDtrack::kTPCin )==0)
61 if ((t->GetStatus()&AliESDtrack::kTPCout)==0) continue;
62 Int_t ns=AliESDtrack::kSPECIES;
63 Double_t p[10];
64 for (Int_t j=0; j<ns; j++) {
65 Double_t mass=masses[j];
66 Double_t mom=t->GetP();
67 Double_t dedx=t->GetTPCsignal()/fMIP;
68 Double_t bethe=Bethe(mom/mass);
69 Double_t sigma=fRes*bethe;
70 if (TMath::Abs(dedx-bethe) > fRange*sigma) {
431be10d 71 p[j]=TMath::Exp(-0.5*fRange*fRange)/sigma;
8c6a71ab 72 continue;
73 }
431be10d 74 p[j]=TMath::Exp(-0.5*(dedx-bethe)*(dedx-bethe)/(sigma*sigma))/sigma;
8c6a71ab 75 }
76 t->SetTPCpid(p);
77 }
78 return 0;
79}