2 #include "AliHLTD0toKpi.h"
3 #include "TDatabasePDG.h"
5 #include "AliESDtrack.h"
7 #include "AliAODVertex.h"
8 #include "AliESDVertex.h"
10 #include "AliVertexerTracks.h"
13 ClassImp(AliHLTD0toKpi)
15 AliHLTD0toKpi::AliHLTD0toKpi()
19 Double_t AliHLTD0toKpi::InvMass(AliESDtrack* d1, AliESDtrack* d2)
21 Double_t mpi=TDatabasePDG::Instance()->GetParticle(211)->Mass();
22 Double_t mK=TDatabasePDG::Instance()->GetParticle(321)->Mass();
25 energy[1] = TMath::Sqrt(mK*mK+d1->GetP()*d1->GetP());
26 energy[0] = TMath::Sqrt(mpi*mpi+d2->GetP()*d2->GetP());
32 Double_t momTot2 = (p1[0]+p2[0])*(p1[0]+p2[0])+
33 (p1[1]+p2[1])*(p1[1]+p2[1])+
34 (p1[2]+p2[2])*(p1[2]+p2[2]);
36 return TMath::Sqrt((energy[0]+energy[1])*(energy[0]+energy[1])-momTot2);
39 void AliHLTD0toKpi::cosThetaStar(AliESDtrack* d1, AliESDtrack* d2,Double_t &D0,Double_t &D0bar)
41 Double_t mD0 = TDatabasePDG::Instance()->GetParticle(421)->Mass();
42 Double_t mpi=TDatabasePDG::Instance()->GetParticle(211)->Mass();
43 Double_t mK=TDatabasePDG::Instance()->GetParticle(321)->Mass();
45 Double_t pStar = TMath::Sqrt(TMath::Power(mD0*mD0-mK*mK-mpi*mpi,2.)-4.*mK*mK*mpi*mpi)/(2.*mD0);
47 Double_t px = d1->Px()+d2->Px();
48 Double_t py = d1->Py()+d2->Py();
49 Double_t pz = d1->Pz()+d2->Pz();
50 Double_t p = TMath::Sqrt(px*px+py*py+pz*pz);
51 Double_t energy = TMath::Sqrt(p*p+mD0*mD0);
53 Double_t beta = p/energy;
54 Double_t gamma = energy/mD0;
57 TVector3 mom(d1->Px(),d1->Py(),d1->Pz());
58 TVector3 momD(px,py,pz);
59 qL = mom.Dot(momD)/momD.Mag();
61 D0 = (qL/gamma-beta*TMath::Sqrt(pStar*pStar+mK*mK))/pStar;
63 TVector3 mom2(d2->Px(),d2->Py(),d2->Pz());
64 TVector3 momD2(px,py,pz);
65 qL = mom2.Dot(momD2)/momD2.Mag();
67 D0bar = (qL/gamma-beta*TMath::Sqrt(pStar*pStar+mK*mK))/pStar;
70 Double_t AliHLTD0toKpi::pointingAngle(AliESDtrack* n, AliESDtrack* p, Double_t *pv, Double_t *sv)
73 TVector3 mom(n->Px()+p->Px(),n->Py()+p->Py(),n->Pz()+p->Pz());
74 TVector3 flight(sv[0]-pv[0],sv[1]-pv[1],sv[2]-pv[2]);
76 double pta = mom.Angle(flight);
78 return TMath::Cos(pta);
81 AliAODVertex* AliHLTD0toKpi::ReconstructSecondaryVertex(TObjArray *trkArray, Double_t b, const AliESDVertex *v)
84 AliESDVertex *vertexESD = 0;
85 AliAODVertex *vertexAOD = 0;
87 AliVertexerTracks *vertexer = new AliVertexerTracks(b);
88 AliESDVertex* fV1 = new AliESDVertex(*v);
89 vertexer->SetVtxStart(fV1);
90 vertexESD = (AliESDVertex*)vertexer->VertexForSelectedESDTracks(trkArray);
91 delete vertexer; vertexer=NULL;
93 if(!vertexESD) return vertexAOD;
95 if(vertexESD->GetNContributors()!=trkArray->GetEntriesFast()) {
96 //AliDebug(2,"vertexing failed");
97 delete vertexESD; vertexESD=NULL;
101 // convert to AliAODVertex
102 Double_t pos[3],cov[6],chi2perNDF;
103 vertexESD->GetXYZ(pos); // position
104 vertexESD->GetCovMatrix(cov); //covariance matrix
105 chi2perNDF = vertexESD->GetChi2toNDF();
106 //dispersion = vertexESD->GetDispersion();
107 delete vertexESD; vertexESD=NULL;
109 Int_t nprongs= trkArray->GetEntriesFast();
110 vertexAOD = new AliAODVertex(pos,cov,chi2perNDF,0x0,-1,AliAODVertex::kUndef,nprongs);