STEER/AOD/AliAODpidUtil.cxx

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   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
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  15
  16 /* $Id: AliAODpidUtil.cxx 38329 2010-01-17 19:17:24Z hristov $ */
  17
  18 //-----------------------------------------------------------------
  19 //           Implementation of the combined PID class
  20 //           For the AOD Class
  21 //           containing information on the particle identification
  22 //      Origin: Rosa Romita, GSI, r.romita@gsi.de
  23 //-----------------------------------------------------------------
  24
  25 #include "TRandom.h"
  26 #include "AliLog.h"
  27 #include "AliPID.h"
  28 #include "AliAODpidUtil.h"
  29 #include "AliAODEvent.h"
  30 #include "AliAODTrack.h"
  31 #include "AliAODPid.h"
  32 #include "AliTRDPIDResponse.h"
  33 #include "AliESDtrack.h"
  34 #include "AliAODMCHeader.h"
  35 #include "AliAODMCParticle.h"
  36
  37 #include <AliDetectorPID.h>
  38
  39 ClassImp(AliAODpidUtil)
  40
  41 //_________________________________________________________________________
  42 Float_t AliAODpidUtil::GetTPCsignalTunedOnData(const AliVTrack *t) const {
  43     AliAODTrack *track = (AliAODTrack *) t;
  44     Float_t dedx = track->GetTPCsignalTunedOnData();
  45     if(dedx > 0) return dedx;
  46
  47     Double_t mom = t->GetTPCmomentum();
  48
  49     dedx = t->GetTPCsignal();
  50     track->SetTPCsignalTunedOnData(dedx);
  51
  52     if(dedx < 20) return dedx;
  53
  54
  55     AliPID::EParticleType type = AliPID::kPion;
  56
  57     AliAODMCHeader *mcHeader = dynamic_cast<AliAODMCHeader*>(track->GetAODEvent()->GetList()->FindObject(AliAODMCHeader::StdBranchName()));
  58     if (mcHeader) {
  59         TClonesArray *mcArray = (TClonesArray*)track->GetAODEvent()->GetList()->FindObject(AliAODMCParticle::StdBranchName());
  60
  61         Bool_t kGood = kTRUE;
  62
  63         Int_t iS = TMath::Abs(((AliAODMCParticle*)mcArray->At(TMath::Abs(t->GetLabel())))->GetPdgCode());
  64         if(iS==AliPID::ParticleCode(AliPID::kElectron)){
  65             type = AliPID::kElectron;
  66         }
  67         else if(iS==AliPID::ParticleCode(AliPID::kMuon)){
  68             type = AliPID::kMuon;
  69         }
  70         else if(iS==AliPID::ParticleCode(AliPID::kPion)){
  71             type = AliPID::kPion;
  72         }
  73         else if(iS==AliPID::ParticleCode(AliPID::kKaon)){
  74             type = AliPID::kKaon;
  75         }
  76         else if(iS==AliPID::ParticleCode(AliPID::kProton)){
  77             type = AliPID::kProton;
  78         }
  79         else if(iS==AliPID::ParticleCode(AliPID::kDeuteron)){ // d
  80             type = AliPID::kDeuteron;
  81         }
  82         else if(iS==AliPID::ParticleCode(AliPID::kTriton)){ // t
  83             type = AliPID::kTriton;
  84         }
  85         else if(iS==AliPID::ParticleCode(AliPID::kHe3)){ // 3He
  86             type = AliPID::kHe3;
  87         }
  88         else if(iS==AliPID::ParticleCode(AliPID::kAlpha)){ // 4He
  89             type = AliPID::kAlpha;
  90         }
  91         else
  92             kGood = kFALSE;
  93
  94         if(kGood){
  95             Double_t bethe=fTPCResponse.GetExpectedSignal(mom,type);
  96             Double_t sigma=fTPCResponse.GetExpectedSigma(mom,t->GetTPCsignalN(),type);
  97             dedx = gRandom->Gaus(bethe,sigma);
  98
  99             if(iS == AliPID::ParticleCode(AliPID::kHe3) || iS == AliPID::ParticleCode(AliPID::kAlpha)) dedx *= 5;
 100         }
 101
 102     }
 103
 104     track->SetTPCsignalTunedOnData(dedx);
 105     return dedx;
 106 }
 107 //_________________________________________________________________________
 108 Float_t AliAODpidUtil::NumberOfSigmasTOF(const AliVParticle *vtrack, AliPID::EParticleType type) const
 109 {
 110   //
 111   // Number of sigma implementation for the TOF
 112   //
 113
 114   AliAODTrack *track=(AliAODTrack*)vtrack;
 115
 116   // look for cached value first
 117   if (track->GetDetectorPID()){
 118     return track->GetDetectorPID()->GetNumberOfSigmas(kTOF, type);
 119   }
 120
 121   Bool_t oldAod=kTRUE;
 122   Double_t sigTOF;
 123   AliAODPid *pidObj = track->GetDetPid();
 124   if (!pidObj) return -999.;
 125   Double_t tofTime=pidObj->GetTOFsignal();
 126   Double_t expTime=fTOFResponse.GetExpectedSignal((AliVTrack*)vtrack,type);
 127   Double_t sigmaTOFPid[AliPID::kSPECIES];
 128   pidObj->GetTOFpidResolution(sigmaTOFPid);
 129   AliAODEvent *event=(AliAODEvent*)track->GetAODEvent();
 130   if (event) {  // protection if the user didn't call GetTrack, which sets the internal pointer
 131     AliTOFHeader* tofH=(AliTOFHeader*)event->GetTOFHeader();
 132     if (tofH && (TMath::Abs(sigmaTOFPid[0]) <= 1.E-16) ) { // new AOD
 133         sigTOF=fTOFResponse.GetExpectedSigma(track->P(),expTime,AliPID::ParticleMassZ(type)); //fTOFResponse is set in InitialiseEvent
 134         tofTime -= fTOFResponse.GetStartTime(vtrack->P());
 135         oldAod=kFALSE;
 136     }
 137   } else {
 138     AliError("pointer to AliAODEvent not found, please call GetTrack to set it");
 139     return -996.;
 140   }
 141   if (oldAod) { // old AOD
 142     if (type <= AliPID::kProton) {
 143       sigTOF=sigmaTOFPid[type];
 144     } else return -998.;  // light nuclei cannot be supported on old AOD because we don't have timeZero resolution
 145   }
 146   if (sigTOF>0) return (tofTime - expTime)/sigTOF;
 147   else return -997.;
 148 }