EvtPsi2JpsiPiPi.hh

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#ifndef EVTPSI2JPSIPIPI_HH
#define EVTPSI2JPSIPIPI_HH
 
#include "EvtGenBase/EvtDecayAmp.hh"
 
#include <array>
#include <string>
 
class EvtDecayBase;
class EvtParticle;
 
// Description: Header file for the model "PSI2JPSIPIPI" which generates
//              psi2S -> J/psi pi+ pi- decays based on hep-ph/1507.07985
 
class EvtPsi2JpsiPiPi : public EvtDecayAmp {
  public:
    EvtPsi2JpsiPiPi();
 
    std::string getName() const override;
    EvtDecayBase* clone() const override;
    void initProbMax() override;
    void init() override;
    void decay( EvtParticle* p ) override;
 
  private:
    bool m_tree;
    double m_phi;    // LO vs NLO mixing angle (radians)
    double m_cosPhi, m_cos2Phi, m_sinPhi, m_sin2Phi;
    // NLO corrections
    static const int m_nQ = 6;    // number of terms in mPiPi interpolation
    std::array<double, m_nQ> m_c0, m_c1, m_c2, m_s1, m_s2;
 
    void setNLOArrays();
};
 
#endif