1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
17 #include "AliHLTVertexer.h"
18 #include "AliTracker.h"
20 #include "AliESDtrack.h"
22 #include "AliESDVertex.h"
23 #include "AliESDEvent.h"
24 #include "AliKFParticle.h"
25 #include "AliKFVertex.h"
27 ClassImp(AliHLTVertexer)
29 AliHLTVertexer::AliHLTVertexer():
35 AliHLTVertexer::AliHLTVertexer(const AliHLTVertexer & ):
41 void AliHLTVertexer::SetESD( AliESDEvent *event )
43 //* Fill fTrackInfo array
48 AliKFParticle::SetField( fESD->GetMagneticField() );
50 Int_t nESDTracks=event->GetNumberOfTracks();
51 fTrackInfos = new AliESDTrackInfo[ nESDTracks ];
53 for (Int_t iTr=0; iTr<nESDTracks; iTr++){
55 AliESDTrackInfo &info = fTrackInfos[iTr];
57 info.fPrimUsedFlag = 0;
59 //* track quality check
61 AliESDtrack *pTrack = event->GetTrack(iTr);
62 if( !pTrack ) continue;
63 if (pTrack->GetKinkIndex(0)>0) continue;
64 if ( !( pTrack->GetStatus()&AliESDtrack::kTPCin ) ) continue;
66 //* Construct KFParticle for the track
68 info.fParticle = AliKFParticle( *pTrack, 211 );
74 void AliHLTVertexer::FindPrimaryVertex( )
76 //* Find event primary vertex
78 int nTracks = fESD->GetNumberOfTracks();
80 const AliKFParticle **vSelected = new const AliKFParticle*[nTracks]; //* Selected particles for vertex fit
81 Int_t *vIndex = new int [nTracks]; //* Indices of selected particles
82 Bool_t *vFlag = new bool [nTracks]; //* Flags returned by the vertex finder
85 for( Int_t i = 0; i<nTracks; i++){
86 if(fTrackInfos[i].fOK ){
87 vSelected[nSelected] = &(fTrackInfos[i].fParticle);
88 vIndex[nSelected] = i;
94 primVtx.SetBeamConstraint(fESD->GetDiamondX(),fESD->GetDiamondY(),0,
95 TMath::Sqrt(fESD->GetSigma2DiamondX()),TMath::Sqrt(fESD->GetSigma2DiamondY()),5.3);
97 primVtx.ConstructPrimaryVertex( vSelected, nSelected, vFlag, 3. );
98 for( Int_t i = 0; i<nSelected; i++){
99 if( vFlag[i] ) fTrackInfos[vIndex[i]].fPrimUsedFlag = 1;
103 AliESDVertex vESD( primVtx.Parameters(), primVtx.CovarianceMatrix(), primVtx.GetChi2(), primVtx.GetNContributors() );
104 fESD->SetPrimaryVertexTracks( &vESD );
112 void AliHLTVertexer::FindV0s( )
116 int nTracks = fESD->GetNumberOfTracks();
117 AliKFVertex primVtx( *fESD->GetPrimaryVertexTracks() );
119 for( Int_t iTr = 0; iTr<nTracks; iTr++ ){ //* first daughter
121 AliESDTrackInfo &info = fTrackInfos[iTr];
122 if( !info.fOK ) continue;
124 for( Int_t jTr = iTr+1; jTr<nTracks; jTr++ ){ //* second daughter
125 AliESDTrackInfo &jnfo = fTrackInfos[jTr];
126 if( !jnfo.fOK ) continue;
128 //* check for different charge
130 if( info.fParticle.GetQ() == jnfo.fParticle.GetQ() ) continue;
132 //* construct V0 mother
134 AliKFParticle V0( info.fParticle, jnfo.fParticle );
138 if( V0.GetNDF()<1 ) continue;
139 if( TMath::Sqrt(TMath::Abs(V0.GetChi2()/V0.GetNDF())) >3. ) continue;
141 //* subtruct daughters from primary vertex
143 AliKFVertex primVtxCopy = primVtx;
145 if( info.fPrimUsedFlag ) primVtxCopy -= info.fParticle;
146 if( jnfo.fPrimUsedFlag ) primVtxCopy -= jnfo.fParticle;
148 //* Check V0 Chi^2 deviation from primary vertex
150 if( V0.GetDeviationFromVertex( primVtxCopy ) >3. ) continue;
152 //* Add V0 to primary vertex to improve the primary vertex resolution
156 //* Set production vertex for V0
158 V0.SetProductionVertex( primVtxCopy );
160 //* Check chi^2 for a case
162 if( TMath::Sqrt( TMath::Abs(V0.GetChi2()/V0.GetNDF()) >3. )) continue;
164 //* Get V0 decay length with estimated error
166 Double_t length, sigmaLength;
167 if( V0.GetDecayLength( length, sigmaLength ) ) continue;
169 //* Reject V0 if it decays too close to the primary vertex
171 if( length <3.*sigmaLength ) continue;
173 //* Get V0 invariant mass
175 // Double_t mass, sigmaMass;
176 //if( V0.GetMass( mass, sigmaMass ) ) continue;
180 AliESDv0 v0ESD( *fESD->GetTrack( iTr ), iTr, *fESD->GetTrack( jTr ), jTr );
182 fESD->AddV0( &v0ESD );