EvtFourBodyPhsp.hh

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#ifndef EVTFOURBODYPHSP_HH
#define EVTFOURBODYPHSP_HH
 
#include "EvtGenBase/EvtDecayProb.hh"
 
#include <array>
#include <utility>
#include <vector>
 
class EvtParticle;
 
class EvtFourBodyPhsp : public EvtDecayProb {
  public:
    enum Shape
    {
        rectangle = 1,
        trapezoid = 2,
        pentagon = 3,
        variable = 4
    };
 
    std::string getName() const override;
    EvtDecayBase* clone() const override;
 
    void init() override;
    void initProbMax() override;
 
    void decay( EvtParticle* parent ) override;
 
  private:
    std::array<double, 4> phspFactor( const double mM, const double m12,
                                      const double m34,
                                      std::array<double, 4>& daughters ) const;
    Shape determineBoundaryShape( const double m12Min, const double m12Max,
                                  const double m34Max,
                                  const double mMother ) const;
 
    std::pair<double, double> generatePairMasses(
        const double m12Min, const double m12Max, const double m34Min,
        const double m34Max, const double mMother,
        const EvtFourBodyPhsp::Shape shape ) const;
    std::pair<double, double> generateRectangle( const double m12Min,
                                                 const double m12Max,
                                                 const double m34Min,
                                                 const double m34Max ) const;
    std::pair<double, double> generateTrapezoid( const double m12Min,
                                                 const double m12Max,
                                                 const double m34Min,
                                                 const double mMother ) const;
 
    std::array<double, 4> m_daughterMasses{ -1, -1, -1, -1 };
 
    double m_m12Min;
    double m_m12Max;
    double m_m34Min;
    double m_m34Max;
 
    double m_trapNorm;
    double m_trapCoeff1;
    double m_trapCoeff2;
 
    double m_pentagonSplit;
    double m_pentagonFraction;
 
    Shape m_boundaryShape;
 
    bool m_stableMother{ true };
    bool m_stableDaughters{ true };
    bool m_fixedBoundary{ true };
};
 
#endif