EvtVubHybrid.hh

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#ifndef EVTVUBHYBRID_HH
#define EVTVUBHYBRID_HH
 
#include "EvtGenBase/EvtDecayIncoherent.hh"
 
#include "EvtGenModels/EvtVubdGamma.hh"
 
#include <memory>
#include <vector>
 
class EvtParticle;
class RandGeneral;
 
// Description:
// Class to generate inclusive B to X_u l nu decays.
// This class is based on EvtVub by Sven Menke with an update to
// generate the inclusive decays in such a way that the right
// mix of inclusive and exclusive decays is obtained:
// "Hybrid Model" by Dominique Fortin.
// NOTE:
// - A set of weights (for bins in the kinematic variables mX, q2, El)
//   is read from DECAY.DEC. This set of weights must be consistent
//   with the other parameters specified (excl. BF, non-res BF, mb, a).
// - If no binning/weights are specified in DECAY.DEC the hybrid
//   reweighting is not activated
 
class EvtVubHybrid : public EvtDecayIncoherent {
  public:
    std::string getName() const override;
 
    EvtDecayBase* clone() const override;
 
    void initProbMax() override;
 
    void init() override;
 
    void decay( EvtParticle* p ) override;
 
    void readWeights( int startArg = 0 );
 
    double getWeight( double mX, double q2, double El );
 
  private:
    double findPFermi();
 
    enum
    {
        nParameters = 3,
        nVariables = 3
    };
 
    bool m_noHybrid =
        false;    // m_noHybrid will be set TRUE if the DECAY.DEC file has no binning or weights
    bool m_storeQplus =
        true;    // m_storeQplus should alwasy be TRUE: writes out Fermi motion parameter
 
    double m_mb = 4.62;        // the b-quark pole mass in GeV (try 4.65 to 4.9)
    double m_a = 2.27;         // Parameter for the Fermi Motion (1.29 is good)
    double m_alphas = 0.22;    // Strong Coupling at m_b (around 0.24)
    double m_dGMax = 3.;       // max dGamma*p2 value;
    int m_nbins = 0;
    double m_masscut = 0.28;
    std::vector<double> m_bins_mX;
    std::vector<double> m_bins_q2;
    std::vector<double> m_bins_El;
    std::vector<double> m_weights;
    std::unique_ptr<EvtVubdGamma> m_dGamma;    // calculates the decay rate
    std::vector<double> m_pf;
};
 
#endif