1 #ifndef ALIRSNMINIPAIR_H
2 #define ALIRSNMINIPAIR_H
5 // This object is used as lightweight temporary container
6 // of all information needed from any input object and
7 // useful for resonance analysis.
11 #include <TLorentzVector.h>
13 class AliRsnMiniParticle;
15 class AliRsnMiniPair : public TObject {
18 AliRsnMiniPair() : fMother(-1), fMotherPDG(0) { }
20 Int_t &Mother() {return fMother;}
21 Int_t &MotherPDG() {return fMotherPDG;}
22 void Fill(AliRsnMiniParticle *p1, AliRsnMiniParticle *p2, Double_t m1, Double_t m2, Double_t refMass);
23 void FillRef(Double_t mass);
24 void InvertP(Bool_t first);
26 Int_t ID(Bool_t mc) const {if (mc) return 1; else return 0;}
28 TLorentzVector &P1 (Bool_t mc) {return fP1 [ID(mc)];}
29 TLorentzVector &P2 (Bool_t mc) {return fP2 [ID(mc)];}
30 TLorentzVector &Sum(Bool_t mc) {return fSum[ID(mc)];}
31 TLorentzVector &Ref(Bool_t mc) {return fRef[ID(mc)];}
33 Double_t Pt(Bool_t mc) const {return fSum[ID(mc)].Pt();}
34 Double_t Pz(Bool_t mc) const {return fSum[ID(mc)].Pz();}
35 Double_t Eta(Bool_t mc) const {return fSum[ID(mc)].Eta();}
36 Double_t InvMass(Bool_t mc) const {return fSum[ID(mc)].M();}
37 Double_t InvMassRes() const;
38 Double_t InvMassDiff() const;
39 Double_t Mt(Bool_t mc) const {return fRef[ID(mc)].Mt();}
40 Double_t Y(Bool_t mc) const {return fRef[ID(mc)].Rapidity();}
41 Double_t PtRatio(Bool_t mc) const;
42 Double_t DipAngle(Bool_t mc) const;
43 Double_t CosThetaStar(Bool_t mc);
47 TLorentzVector fP1 [2]; // 1st daughter momentum
48 TLorentzVector fP2 [2]; // 2nd daughter momentum
49 TLorentzVector fSum[2]; // sum of momenta
50 TLorentzVector fRef[2]; // same as 'fSum' but with nominal resonance mass
52 Int_t fMother; // label of mothers (when common)
53 Int_t fMotherPDG; // PDG code of mother (when common)
55 ClassDef(AliRsnMiniPair,1)
58 inline void AliRsnMiniPair::FillRef(Double_t mass)
61 // Fill ref 4-vectors using the passed mass and the values in 'sum'
65 for (i = 0; i < 2; i++) {
66 fRef[i].SetXYZM(fSum[i].X(), fSum[i].Y(), fSum[i].Z(), mass);
70 inline Double_t AliRsnMiniPair::InvMassRes() const
73 // Return invariant mass resolution
76 if (fSum[1].M() <= 0.0) return 1E20;
78 return (fSum[0].M() - fSum[1].M()) / fSum[1].M();
81 inline Double_t AliRsnMiniPair::InvMassDiff() const
84 // Return invariant mass resolution
87 if (fSum[1].M() <= 0.0) return 1E20;
89 return (fSum[0].M() - fSum[1].M());
92 inline Double_t AliRsnMiniPair::PtRatio(Bool_t mc) const
95 // Return ratio of transverse momenta of daughters
98 Double_t num = TMath::Abs(fP1[ID(mc)].Perp() - fP2[ID(mc)].Perp());
99 Double_t den = TMath::Abs(fP1[ID(mc)].Perp() + fP2[ID(mc)].Perp());
101 if (den <= 0.0) return 1E20;
106 inline Double_t AliRsnMiniPair::DipAngle(Bool_t mc) const
109 // Opening angle in a Z-T space
112 const TLorentzVector &p1 = fP1[ID(mc)];
113 const TLorentzVector &p2 = fP2[ID(mc)];
115 return ((p1.Perp() * p2.Perp() + p1.Z() * p2.Z()) / p1.Mag() / p2.Mag());