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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. * | |
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 ITS 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 | ||
e1e6896f | 22 | #include <TMath.h> |
23 | ||
8c6a71ab | 24 | #include "AliITSpidESD.h" |
8c6a71ab | 25 | #include "AliESDtrack.h" |
26 | ||
27 | ClassImp(AliITSpidESD) | |
28 | ||
8c6a71ab | 29 | |
e62c1aea | 30 | //______________________________________________________________________ |
31 | AliITSpidESD::AliITSpidESD():TObject(){ | |
32 | //Default constructor | |
33 | ||
34 | } | |
8c6a71ab | 35 | |
25fee9b6 | 36 | Double_t AliITSpidESD::Bethe(Double_t p,Double_t mass) { |
37 | ||
38 | Double_t mom=p*1000;//MeV | |
39 | Double_t Mass=mass*1000;//Mev | |
40 | Float_t dens =2.33; //g cm-3 | |
41 | Double_t K=0.307075;//MeVcm^2/g | |
42 | Double_t ZovA=0.49848; | |
43 | Double_t me=0.511;//MeV/c^2 | |
44 | Double_t I=173./1000000.;//MeV | |
45 | Double_t En=TMath::Sqrt(mom*mom+Mass*Mass);//MeV | |
46 | Double_t gamma=En/Mass; | |
47 | Double_t beta=mom/En; | |
48 | Double_t Tmax=2*me*beta*beta*gamma*gamma/(1+2*gamma*me/Mass+(me/Mass)*(me/Mass)); | |
49 | Double_t deltaover2=28.816*1e-6*TMath::Sqrt(dens*ZovA)+TMath::Log(beta*gamma)-0.5; | |
50 | return K*ZovA*1/(beta*beta)*(0.5*TMath::Log(2*me*beta*beta*gamma*gamma*Tmax/(I*I))-beta*beta-deltaover2)*2.33*1000*0.03-37; | |
51 | ||
52 | ||
53 | } |