RICH/AliRICHTracker.cxx

   1 #include "AliRICHTracker.h"
   2 #include <AliESD.h>
   3 #include <TVector3.h>
   4 #include <TTree.h>
   5 #include "AliRICH.h"
   6 #include "AliRICHHelix.h"
   7 #include <AliMagF.h>
   8 #include "AliRICHRecon.h"
   9 #include <AliStack.h>
  10 #include <TParticle.h>
  11 #include <TDatabasePDG.h>
  12 #include <TMath.h>
  13 ClassImp(AliRICHTracker)
  14 //__________________________________________________________________________________________________
  15 Int_t AliRICHTracker::PropagateBack(AliESD *pESD)
  16 {
  17   //invoked by AliRecontruction for RICH
  18   //if ESD doesn't contain tracks, try to reconstruct with particle from STACK
  19   //(this case is just to forsee a standalone RICH simulation
  20
  21   AliDebug(1,"Start pattern recognition");
  22   if(pESD->GetNumberOfTracks()) RecWithESD(pESD);
  23   else
  24     RecWithStack();
  25   AliDebug(1,"Stop pattern recognition");
  26
  27   return 0; // error code: 0=no error;
  28 } //pure virtual from AliTracker
  29 //__________________________________________________________________________________________________
  30 void AliRICHTracker::RecWithESD(AliESD *pESD)
  31 {
  32   //recontruction from ESD
  33   //
  34   Int_t iNtracks=pESD->GetNumberOfTracks();
  35   Double_t b=GetFieldMap()->SolenoidField()/10;// magnetic field in Tesla
  36   AliDebug(1,Form("Start with %i tracks in %f Tesla field",iNtracks,b));
  37   Double_t xb[3],pb[3];//tmp storage for track parameters
  38   TVector3 x0(0,0,0); TVector3 p0(0,0,0);//tmp storage for AliRICHHelix
  39
  40   AliRICH *pRich=((AliRICH*)gAlice->GetDetector("RICH"));
  41
  42   for(Int_t iTrackN=0;iTrackN<iNtracks;iTrackN++){//ESD tracks loop
  43     AliESDtrack *pTrack = pESD->GetTrack(iTrackN);// get next reconstructed track
  44 //  if((pTrack->GetStatus()&AliESDtrack::kTOFout)==0) continue; //ignore tracks not recontructed by TOF
  45     pTrack->GetXYZ(xb);
  46       pTrack->GetPxPyPz(pb);
  47           Int_t status=pTrack->GetStatus()&AliESDtrack::kTOFout;//get running track parameters
  48     AliDebug(1,Form("Track %i pmod=%f mass=%f stat=%i",iTrackN,pTrack->GetP(),pTrack->GetMass(),status));
  49     x0.SetXYZ(xb[0],xb[1],xb[2]); p0.SetXYZ(xb[0],xb[1],xb[2]);
  50     AliRICHHelix helix(x0,p0,pTrack->GetSign(),b);
  51     Int_t iChamber=helix.RichIntersect(pRich->P());
  52     AliDebug(1,Form("intersection with %i chamber found",iChamber));
  53     if(!iChamber) continue;//intersection with no chamber found
  54
  55     Double_t distMip=9999; //min distance between clusters and track position on PC
  56     Int_t iMipId=0; //index of that min distance cluster
  57     for(Int_t iClusN=0;iClusN<pRich->Clusters(iChamber)->GetEntries();iClusN++){//clusters loop for intersected chamber
  58       AliRICHcluster *pClus=(AliRICHcluster*)pRich->Clusters(iChamber)->UncheckedAt(iClusN);//get pointer to current cluster
  59       Double_t distCurrent=pClus->DistTo(helix.PosPc());//ditance between current cluster and helix intersection with PC
  60       if(distCurrent<distMip){distMip=distCurrent;iMipId=iClusN;}//find cluster nearest to the track
  61
  62       AliDebug(1,Form("Ploc (%f,%f,%f) dist= %f",helix.Ploc().Mag(),helix.Ploc().Theta()*TMath::RadToDeg(),
  63                                                                     helix.Ploc().Phi()*TMath::RadToDeg(),pClus->DistTo(helix.PosPc())));
  64     }////clusters loop for intersected chamber
  65
  66     AliDebug(1,Form("Min distance cluster: %i dist is %f",iMipId,distMip));
  67
  68     AliRICHRecon recon(&helix,pRich->Clusters(iChamber),iMipId);
  69     Double_t thetaCerenkov=recon.ThetaCerenkov(); //search for mean Cerenkov angle for this track
  70     AliDebug(1,Form("FINAL Theta Cerenkov=%f",thetaCerenkov));
  71     pTrack->SetRICHsignal(thetaCerenkov);
  72
  73     Double_t richPID[5]={0.2,0.2,0.2,0.2,0.2}; //start with equal probs for (e,mu,pi,k,p)
  74     CalcProb(thetaCerenkov,p0.Mag(),richPID);
  75     pTrack->SetRICHpid(richPID);
  76
  77   }//ESD tracks loop
  78   AliDebug(1,"Stop.");
  79 } //RecWithESD
  80 //__________________________________________________________________________________________________
  81 void AliRICHTracker::RecWithStack()
  82 {
  83   // reconstruction for particles from STACK
  84   //
  85   AliRICH *pRich=((AliRICH*)gAlice->GetDetector("RICH"));
  86
  87   pRich->GetLoader()->GetRunLoader()->LoadHeader();pRich->GetLoader()->GetRunLoader()->LoadKinematics();
  88   AliStack *pStack =   pRich->GetLoader()->GetRunLoader()->Stack();
  89   Int_t iNtracks=pStack->GetNtrack();
  90
  91   Double_t b=GetFieldMap()->SolenoidField()/10;// magnetic field in Tesla
  92   AliDebug(1,Form("Start with simulated %i tracks in %f Tesla field",iNtracks,b));
  93   TVector3 x0(0,0,0); TVector3 p0(0,0,0);//tmp storage for AliRICHHelix
  94
  95
  96   for(Int_t iTrackN=0;iTrackN<iNtracks;iTrackN++){//ESD tracks loop
  97     TParticle *pParticle = pStack->Particle(iTrackN);
  98     p0.SetMagThetaPhi(pParticle->P(),pParticle->Theta(),pParticle->Phi());
  99     x0.SetXYZ(pParticle->Vx(),pParticle->Vy(),pParticle->Vz());
 100     AliRICHHelix helix(x0,p0,Int_t(pParticle->GetPDG()->Charge()/3+0.1),b);
 101     Int_t iChamber=helix.RichIntersect(pRich->P());
 102     AliDebug(1,Form("intersection with %i chamber found",iChamber));
 103     if(!iChamber) continue;//intersection with no chamber found
 104
 105     Double_t distMip=9999; //min distance between clusters and track position on PC
 106     Int_t iMipId=0; //index of that min distance cluster
 107     for(Int_t iClusN=0;iClusN<pRich->Clusters(iChamber)->GetEntries();iClusN++){//clusters loop for intersected chamber
 108       AliRICHcluster *pClus=(AliRICHcluster*)pRich->Clusters(iChamber)->UncheckedAt(iClusN);//get pointer to current cluster
 109       Double_t distCurrent=pClus->DistTo(helix.PosPc());//ditance between current cluster and helix intersection with PC
 110       if(distCurrent<distMip){distMip=distCurrent;iMipId=iClusN;}//find cluster nearest to the track
 111
 112       AliDebug(1,Form("Ploc (%f,%f,%f) dist= %f",helix.Ploc().Mag(),helix.Ploc().Theta()*TMath::RadToDeg(),
 113                                                                     helix.Ploc().Phi()*TMath::RadToDeg(),pClus->DistTo(helix.PosPc())));
 114     }////clusters loop for intersected chamber
 115
 116     AliDebug(1,Form("Min distance cluster: %i dist is %f",iMipId,distMip));
 117
 118     AliRICHRecon recon(&helix,pRich->Clusters(iChamber),iMipId);
 119     Double_t thetaCerenkov=recon.ThetaCerenkov(); //search for mean Cerenkov angle for this track
 120     AliDebug(1,Form("FINAL Theta Cerenkov=%f",thetaCerenkov));
 121 //    pTrack->SetRICHsignal(thetaCerenkov);
 122
 123     Double_t richPID[5]={0.2,0.2,0.2,0.2,0.2}; //start with equal probs for (e,mu,pi,k,p)
 124     CalcProb(thetaCerenkov,p0.Mag(),richPID);
 125
 126   }//ESD tracks loop
 127   AliDebug(1,"Stop.");
 128 } //RecWithStack
 129
 130 Int_t AliRICHTracker::LoadClusters(TTree *pTree)
 131 {
 132 // Load clusters for RICH
 133   AliDebug(1,"Start.");  pTree->GetEntry(0);  AliDebug(1,"Stop."); return 0;
 134 }
 135
 136 //__________________________________________________________________________________________________
 137 void AliRICHTracker::CalcProb(Double_t thetaCer,Double_t pmod, Double_t *richPID)
 138 {
 139 //
 140   Double_t height[5];Double_t totalHeight=0;
 141   Int_t code[5]={kElectron,kMuonPlus,kPiPlus,kKPlus,kProton};
 142   TDatabasePDG *db = new TDatabasePDG();
 143   for(Int_t iPart=0;iPart<4;iPart++){
 144     Double_t mass = db->GetParticle(code[iPart])->Mass();
 145     Double_t refIndex=AliRICHParam::IndOfRefC6F14(6.755);
 146     Double_t cosThetaTh = TMath::Sqrt(mass*mass+pmod*pmod)/(refIndex*pmod);
 147     if(cosThetaTh>=1) {break;}
 148     Double_t thetaTh = TMath::ACos(cosThetaTh);
 149     Double_t sinThetaThNorm = TMath::Sin(thetaTh)/TMath::Sqrt(1-1/(refIndex*refIndex));
 150     Double_t sigmaThetaTh = (0.014*(1/sinThetaThNorm-1) + 0.0043)*1.25;
 151     height[iPart] = TMath::Gaus(thetaCer,thetaTh,sigmaThetaTh);
 152     totalHeight +=height[iPart];
 153   }
 154   for(Int_t iPart=0;iPart<5;iPart++) richPID[iPart] = height[iPart]/totalHeight;
 155 }//CalcProb