PionZeroList.h

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#ifndef Physics_Analysis_PionZeroList_H
#define Physics_Analysis_PionZeroList_H
 
#include "CLHEP/Vector/LorentzVector.h"
#include "CLHEP/Vector/ThreeVector.h"
#include <algorithm>
#include <vector>
using namespace CLHEP;
using CLHEP::Hep3Vector;
using CLHEP::HepLorentzVector;
typedef std::vector<Hep3Vector>       Vp3;
typedef std::vector<HepLorentzVector> Vp4;
 
class PionZero {
public:
  PionZero( HepLorentzVector& vp_gam_1, int& index_gam_1, HepLorentzVector& vp_gam_2,
            int& index_gam_2 );
  PionZero() {};
  int              get_index( int i ) { return i > 0 ? m_index_2 : m_index_1; }
  double           get_mass() { return m_inv_mass; }
  double           get_goodness() { return m_goodness; }
  void             cal_goodness( int good_method ); // 0: mass diff; 1: chi^2; 2: ...???
  HepLorentzVector get_gam_vp( int i ) { return i > 0 ? m_vp_2 : m_vp_1; }
  HepLorentzVector get_pi0_vp() { return m_vp_total; }
 
private:
  int              m_index_1, m_index_2, m_good_method;
  HepLorentzVector m_vp_1, m_vp_2, m_vp_total;
  double           m_goodness; // desribe how good of a pi0
  double           m_inv_mass;
};
 
class PionZeroList {
public:
  PionZeroList( Vp4& input_vp ); // initial photon four-momentum list input
  void set_cut( int index, double cut );
  void sort();    // sort all pion0 list with goodness( lower is better )
  void reduce();  // delete all the pion0 with re-used photons
  void print();   // print all information in pion0 list
  void refresh(); // after reduce and sort, we should refresh the mom list
  int  get_num_pi0() { return m_num_pi0; }
  Vp4  get_pi0_list() { return m_pi0_vp; }
 
  class f_less {
  public:
    bool operator()( PionZero& p1, PionZero& p2 ) const {
      return p1.get_goodness() < p2.get_goodness();
    }
  };
 
private:
  Vp4                   m_gam_vp, m_pi0_vp;
  std::vector<PionZero> Vpi0_list;
  double                m_low_cut, m_high_cut; // mass cuts of pion0
  int                   m_num_pi0;
};
 
#endif