KFVertex.h

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//---------------------------------------------------------------------------------
// The KFVertex class
// .
// @author  S.Gorbunov, I.Kisel
// @version 1.0
// @since   13.05.07
//
// Class to reconstruct and store primary and secondary vertices.
// The method is described in CBM-SOFT note 2007-003,
// ``Reconstruction of decayed particles based on the Kalman filter'',
// http://www.gsi.de/documents/DOC-2007-May-14-1.pdf
//
// This class is ALICE interface to general mathematics in KFParticleBase
//
//  -= Copyright &copy ALICE HLT Group =-
//_________________________________________________________________________________

#ifndef KFVERTEX_H
#define KFVERTEX_H

#include "KFParticle.h"
#include "KFPVertex.h"

class KFVertex : public KFParticle {

 public:
  //*
  //*  INITIALIZATION
  //*

  //* Constructor (empty)

  KFVertex() : KFParticle(), fIsConstrained(0) {}

  //* Destructor (empty)

  ~KFVertex() {}

  //* Initialisation from VVertex

  KFVertex(const KFPVertex &vertex);

  //*
  //*  ACCESSORS
  //*

  //* Number of tracks composing the vertex

  Int_t GetNContributors() const { return fIsConstrained ? fNDF / 2 : (fNDF + 3) / 2; }

  //*
  //* CONSTRUCTION OF THE VERTEX BY ITS DAUGHTERS
  //* USING THE KALMAN FILTER METHOD
  //*

  //* Simple way to construct vertices ex. D0 = Pion + Kaon;

  void operator+=(const KFParticle &Daughter);

  //* Subtract particle from vertex

  KFVertex operator-(const KFParticle &Daughter) const;

  void operator-=(const KFParticle &Daughter);

  //* Set beam constraint to the primary vertex

  void SetBeamConstraint(float X, float Y, float Z, float ErrX, float ErrY, float ErrZ);

  //* Set beam constraint off

  void SetBeamConstraintOff();

  //* Construct vertex with selection of tracks (primary vertex)

  void ConstructPrimaryVertex(const KFParticle *vDaughters[], int NDaughters, Bool_t vtxFlag[], float ChiCut = 3.5);

 protected:
  Bool_t fIsConstrained; // Is the beam constraint set
};

//---------------------------------------------------------------------
//
//     Inline implementation of the KFVertex methods
//
//---------------------------------------------------------------------

inline void KFVertex::operator+=(const KFParticle &Daughter)
{
  KFParticle::operator+=(Daughter);
}

inline void KFVertex::operator-=(const KFParticle &Daughter)
{
  Daughter.SubtractFromVertex(*this);
}

inline KFVertex KFVertex::operator-(const KFParticle &Daughter) const
{
  KFVertex tmp = *this;
  Daughter.SubtractFromVertex(tmp);
  return tmp;
}

#endif