| 03d23846 |
1 | #ifndef ALIRSNMINIPAIR_H |
| 2 | #define ALIRSNMINIPAIR_H |
| 3 | |
| 4 | // |
| 5 | // This object is used as lightweight temporary container |
| 6 | // of all information needed from any input object and |
| 7 | // useful for resonance analysis. |
| 8 | // |
| 9 | |
| 10 | #include <TObject.h> |
| 11 | #include <TLorentzVector.h> |
| 12 | |
| 13 | class AliRsnMiniParticle; |
| 14 | |
| 15 | class AliRsnMiniPair : public TObject { |
| 16 | public: |
| 17 | |
| 18 | AliRsnMiniPair() : fMother(-1), fMotherPDG(0) { } |
| 19 | |
| 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 | |
| 25 | Int_t ID(Bool_t mc) const {if (mc) return 1; else return 0;} |
| 26 | |
| 27 | TLorentzVector& P1 (Bool_t mc) {return fP1 [ID(mc)];} |
| 28 | TLorentzVector& P2 (Bool_t mc) {return fP2 [ID(mc)];} |
| 29 | TLorentzVector& Sum(Bool_t mc) {return fSum[ID(mc)];} |
| 30 | TLorentzVector& Ref(Bool_t mc) {return fRef[ID(mc)];} |
| 31 | |
| 32 | Double_t Pt(Bool_t mc) const {return fSum[ID(mc)].Pt();} |
| 33 | Double_t Pz(Bool_t mc) const {return fSum[ID(mc)].Pz();} |
| 34 | Double_t Eta(Bool_t mc) const {return fSum[ID(mc)].Eta();} |
| 35 | Double_t InvMass(Bool_t mc) const {return fSum[ID(mc)].M();} |
| 36 | Double_t InvMassRes() const; |
| 37 | Double_t Mt(Bool_t mc) const {return fRef[ID(mc)].Mt();} |
| 38 | Double_t Y(Bool_t mc) const {return fRef[ID(mc)].Rapidity();} |
| 39 | Double_t PtRatio(Bool_t mc) const; |
| 40 | Double_t DipAngle(Bool_t mc) const; |
| 41 | Double_t CosThetaStar(Bool_t mc); |
| 42 | |
| 43 | private: |
| 44 | |
| 45 | TLorentzVector fP1 [2]; // 1st daughter momentum |
| 46 | TLorentzVector fP2 [2]; // 2nd daughter momentum |
| 47 | TLorentzVector fSum[2]; // sum of momenta |
| 48 | TLorentzVector fRef[2]; // same as 'fSum' but with nominal resonance mass |
| 49 | |
| 50 | Int_t fMother; // label of mothers (when common) |
| 51 | Int_t fMotherPDG; // PDG code of mother (when common) |
| 52 | |
| 53 | ClassDef(AliRsnMiniPair,1) |
| 54 | }; |
| 55 | |
| 56 | inline void AliRsnMiniPair::FillRef(Double_t mass) |
| 57 | { |
| 58 | // |
| 59 | // Fill ref 4-vectors using the passed mass and the values in 'sum' |
| 60 | // |
| 61 | |
| 62 | Int_t i; |
| 63 | for (i = 0; i < 2; i++) { |
| 64 | fRef[i].SetXYZM(fSum[i].X(), fSum[i].Y(), fSum[i].Z(), mass); |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | inline Double_t AliRsnMiniPair::InvMassRes() const |
| 69 | { |
| 70 | // |
| 71 | // Return invariant mass resolution |
| 72 | // |
| 73 | |
| 74 | if (fSum[1].M() <= 0.0) return 1E20; |
| 75 | |
| 76 | return (fSum[0].M() - fSum[1].M()) / fSum[1].M(); |
| 77 | } |
| 78 | |
| 79 | inline Double_t AliRsnMiniPair::PtRatio(Bool_t mc) const |
| 80 | { |
| 81 | // |
| 82 | // Return ratio of transverse momenta of daughters |
| 83 | // |
| 84 | |
| 85 | Double_t num = TMath::Abs(fP1[ID(mc)].Perp() - fP2[ID(mc)].Perp()); |
| 86 | Double_t den = TMath::Abs(fP1[ID(mc)].Perp() + fP2[ID(mc)].Perp()); |
| 87 | |
| 88 | if (den <= 0.0) return 1E20; |
| 89 | |
| 90 | return num / den; |
| 91 | } |
| 92 | |
| 93 | inline Double_t AliRsnMiniPair::DipAngle(Bool_t mc) const |
| 94 | { |
| 95 | // |
| 96 | // Opening angle in a Z-T space |
| 97 | // |
| 98 | |
| 99 | const TLorentzVector &p1 = fP1[ID(mc)]; |
| 100 | const TLorentzVector &p2 = fP2[ID(mc)]; |
| 101 | |
| 102 | return ((p1.Perp() * p2.Perp() + p1.Z() * p2.Z()) / p1.Mag() / p2.Mag()); |
| 103 | } |
| 104 | |
| 105 | #endif |
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