Correct formula for phi, in case of current local X <0, in GetLocalXat and GetPhiZat
[u/mrichter/AliRoot.git] / ITS / AliITSpidESD.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. *
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
1fad94b4 16/* $Id$ */
17
8c6a71ab 18//-----------------------------------------------------------------
19// Implementation of the ITS PID class
20// Very naive one... Should be made better by the detector experts...
21// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
22//-----------------------------------------------------------------
23
e1e6896f 24#include <TMath.h>
25
8c6a71ab 26#include "AliITSpidESD.h"
8c6a71ab 27#include "AliESDtrack.h"
28
29ClassImp(AliITSpidESD)
30
8c6a71ab 31
e62c1aea 32//______________________________________________________________________
33AliITSpidESD::AliITSpidESD():TObject(){
34 //Default constructor
35
36}
8c6a71ab 37
25fee9b6 38Double_t AliITSpidESD::Bethe(Double_t p,Double_t mass) {
39
40 Double_t mom=p*1000;//MeV
41 Double_t Mass=mass*1000;//Mev
42 Float_t dens =2.33; //g cm-3
43 Double_t K=0.307075;//MeVcm^2/g
44 Double_t ZovA=0.49848;
45 Double_t me=0.511;//MeV/c^2
46 Double_t I=173./1000000.;//MeV
47 Double_t En=TMath::Sqrt(mom*mom+Mass*Mass);//MeV
48 Double_t gamma=En/Mass;
49 Double_t beta=mom/En;
50 Double_t Tmax=2*me*beta*beta*gamma*gamma/(1+2*gamma*me/Mass+(me/Mass)*(me/Mass));
51 Double_t deltaover2=28.816*1e-6*TMath::Sqrt(dens*ZovA)+TMath::Log(beta*gamma)-0.5;
38013a1a 52 Double_t FNor=0.009164; //normalizing to 1 at the minimum of ionization
1fad94b4 53
54 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*FNor;
25fee9b6 55
56
57}