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//--------------------------------------------------------------------------------------------------
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// $Id: DecayParticle.h,v 1.27 2009/07/13 11:00:28 loizides Exp $
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//
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// DecayParticle
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//
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// The decay particle class is for use in vertexing based analyses. It
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// stores vertex fit information (including four momentum) and links to daughters.
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//
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// Note that Charge() is still computed as a recursive loop over daughters, as inherited from
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// CompositeParticle, but momentum is returned from the internally stored four vector.
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//
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// Authors: C.Paus, J.Bendavid
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//--------------------------------------------------------------------------------------------------
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#ifndef MITANA_DATATREE_DECAYPARTICLE_H
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#define MITANA_DATATREE_DECAYPARTICLE_H
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#include <TDatabasePDG.h>
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#include <TParticlePDG.h>
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#include "MitCommon/DataFormats/interface/Vect4M.h"
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#include "MitAna/DataTree/interface/DaughterData.h"
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#include "MitAna/DataTree/interface/Vertex.h"
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#include "MitAna/DataCont/interface/RefArray.h"
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namespace mithep
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{
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class DecayParticle : public Particle
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{
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public:
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DecayParticle() :
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fAbsPdgId(0), fChi2(0), fNdof(0), fMassError(0),
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fLxy(0), fLxyError(0), fDxy(0), fDxyError(0), fLz(0), fLzError(0) {}
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DecayParticle(Int_t absPdgId) :
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fAbsPdgId(absPdgId), fChi2(0), fNdof(0), fMassError(0),
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fLxy(0), fLxyError(0), fDxy(0), fDxyError(0), fLz(0), fLzError(0) {}
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void AddDaughterData(const DaughterData *dd)
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{ fDaughterData.Add(dd); ClearCharge(); }
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UInt_t AbsPdgId() const { return fAbsPdgId; }
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Double_t Chi2() const { return fChi2; }
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const Particle *Daughter(UInt_t i) const { return DaughterDat(i)->Original(); }
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const DaughterData *DaughterDat(UInt_t i) const { return fDaughterData.At(i); }
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Double_t Dxy() const { return fDxy; }
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Double_t DxyError() const { return fDxyError; }
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Bool_t HasDaughter(const Particle *p) const;
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Bool_t HasCommonDaughter(const DecayParticle *p) const;
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Bool_t HasPriVertex() const { return fPriVtx.IsValid(); }
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Bool_t HasPriVertex(const Vertex *v)
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const { return fPriVtx.RefsObject(v); }
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Bool_t HasSameDaughters(const DecayParticle *p) const;
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Double_t Lxy() const { return fLxy; }
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Double_t LxyError() const { return fLxyError; }
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Double_t Lz() const { return fLz; }
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Double_t LzError() const { return fLzError; }
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Double_t MassError() const { return fMassError; }
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UShort_t Ndof() const { return fNdof; }
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UInt_t NDaughters() const { return fDaughterData.Entries(); }
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EObjType ObjType() const { return kDecayParticle; }
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TParticlePDG *ParticlePdgEntry() const;
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Double_t PdgMass() const;
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const Vertex *PriVertex() const { return fPriVtx.Obj(); }
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Double_t Prob() const { return TMath::Prob(fChi2,fNdof); }
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const ThreeVector &Position() const;
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const ThreeVector RelativePosition() const;
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Bool_t SharedLayer(Track::EHitLayer l) const { return fSharedLayers.TestBit(l); }
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const BitMask48 &SharedLayers() const { return fSharedLayers; }
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UInt_t NSharedHits() const { return fSharedLayers.NBitsSet(); }
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void SetAbsPdgId(UInt_t apid) { fAbsPdgId=apid; }
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void SetChi2(Double_t chi2) { fChi2 = chi2; }
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void SetDxy(Double_t dxy) { fDxy = dxy; ClearPos(); }
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void SetDxyError(Double_t dxyError) { fDxyError = dxyError; }
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void SetLxy(Double_t lxy) { fLxy = lxy; ClearPos(); }
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void SetLxyError(Double_t lxyError) { fLxyError = lxyError; }
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void SetLz(Double_t lz) { fLz = lz; ClearPos(); }
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void SetLzError(Double_t lzError) { fLzError = lzError; }
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void SetMassError(Double_t massError) { fMassError = massError; }
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void SetMom(Double_t px, Double_t py, Double_t pz, Double_t e);
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void SetMom(const FourVector &p)
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{ fMomentum = p; ClearMom(); ClearPos(); }
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void SetNdof(UShort_t ndof) { fNdof = ndof; }
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void SetPriVertex(const Vertex *v) { fPriVtx = v; ClearPos(); }
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void SetSharedLayer(Track::EHitLayer l) { fSharedLayers.SetBit(l); }
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void SetSharedLayers(const BitMask48 &layers) { fSharedLayers = layers; }
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using TObject::Error;
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protected:
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void ClearPos() const { fCachePosFlag.ClearCache(); }
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Double_t GetCharge() const;
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void GetMom() const;
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void GetPos() const;
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UInt_t fAbsPdgId; //absolute value of pid code
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Double32_t fChi2; //[0,0,12]chi-squared of fit
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UShort_t fNdof; //degrees of freedom for fit
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Double32_t fMassError; //[0,0,14]fitted mass error
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Double32_t fLxy; //[0,0,14]fitted lxy (decay length)
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Double32_t fLxyError; //[0,0,14]fitted lxy error
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Double32_t fDxy; //[0,0,14]fitted impact parameter
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Double32_t fDxyError; //[0,0,14]fitted impact parameter error
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Double32_t fLz; //[0,0,14]fitted lz (decay length)
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Double32_t fLzError; //[0,0,14]fitted lz error
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Vect4M fMomentum; //momentum fourvector
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RefArray<DaughterData> fDaughterData; //momentum of daughters at vertex
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Ref<Vertex> fPriVtx; //reference to primary vertex
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BitMask48 fSharedLayers; //layer mask for shared hits from daughter particles
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mutable CacheFlag fCachePosFlag; //||cache validity flag for position
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mutable ThreeVector fCachedPos; //!cached momentum vector (filled by derived classes)
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ClassDef(DecayParticle, 2) // Decay particle class
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};
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}
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//--------------------------------------------------------------------------------------------------
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inline Double_t mithep::DecayParticle::GetCharge() const
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{
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// Return sum of charge of daughter particles.
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Double_t charge = 0;
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for (UInt_t i=0; i<NDaughters(); ++i)
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charge += DaughterDat(i)->Charge();
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return charge;
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}
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//--------------------------------------------------------------------------------------------------
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inline void mithep::DecayParticle::GetMom() const
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{
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// Get momentum values from stored values.
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fCachedMom.SetCoordinates(fMomentum.Pt(), fMomentum.Eta(), fMomentum.Phi(), fMomentum.M());
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}
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//--------------------------------------------------------------------------------------------------
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inline TParticlePDG *mithep::DecayParticle::ParticlePdgEntry() const
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{
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// Return entry to pdg database for the particle.
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return TDatabasePDG::Instance()->GetParticle(fAbsPdgId);
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}
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//--------------------------------------------------------------------------------------------------
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inline void mithep::DecayParticle::SetMom(Double_t px, Double_t py, Double_t pz, Double_t e)
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{
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// Set four vector.
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fMomentum.SetXYZT(px,py,pz,e);
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ClearMom();
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ClearPos();
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}
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//--------------------------------------------------------------------------------------------------
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inline const mithep::ThreeVector &mithep::DecayParticle::Position() const
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{
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// Return cached momentum value.
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if (!fCachePosFlag.IsValid()) {
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GetPos();
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fCachePosFlag.SetValid();
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}
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return fCachedPos;
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}
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//--------------------------------------------------------------------------------------------------
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inline void mithep::DecayParticle::GetPos() const
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{
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// Return absolute position of decay.
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const mithep::Vertex *pv = PriVertex();
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if (pv)
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fCachedPos = pv->Position() + RelativePosition();
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else
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fCachedPos = RelativePosition();
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}
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//--------------------------------------------------------------------------------------------------
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inline const mithep::ThreeVector mithep::DecayParticle::RelativePosition() const
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{
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// Compute the position vector of the decay vertex relative to the primary vertex.
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mithep::ThreeVector dz(0,0,fLz*TMath::Abs(Pz())/Pz());
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mithep::ThreeVector momPerp(Px(),Py(),0);
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mithep::ThreeVector zHat(0,0,1.0);
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mithep::ThreeVector dxy = -momPerp.Cross(zHat)*fDxy/momPerp.R();
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mithep::ThreeVector dlxy = momPerp*fLxy/momPerp.R();
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return (dxy+dlxy+dz);
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}
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#endif
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