EvtVubdGamma.hh

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#ifndef EVTVUBDGAMMA_HH
#define EVTVUBDGAMMA_HH

// Description:
//    3                                         2                2
//   d Gamma                 /   _      _ _2  mb           _2  mb
//  ---------- = 12 Gamma   | (1+x-z)(z-x-p ) -- W  + (1-z+p ) -- W
//         _ 2           0   \                 2  1             2  2
//  dx dz dp                                   2
//                                _   _  _2  mb                 2   \.
//                             + [x(z-x)-p ] -- (W + 2mb W  + mb W ) |
//                                            4   3       4       5 /
//
//   with
//        2 E           2
//           l    _2   p        2 v.p    _
//   x = ------ , p = --- , z = ------ , x = 1-x
//         mb           2         mb
//                    mb
//
//   the triple differential decay rate according to
//   hep-ph/9905351 v2

class EvtVubdGamma final {
  public:
    // Constructors

    EvtVubdGamma( const double& alphas );

    // Operators

    // Selectors

    // Modifiers

    // Methods

    double getdGdxdzdp( const double& x, const double& z, const double& p2 );

  protected:
    // Helper functions

    double delta( const double& x, const double& xmin, const double& xmax );

    double getW1nodelta( const double& x, const double& z, const double& p2 );

    double getW2nodelta( const double& x, const double& z, const double& p2 );

    double getW3nodelta( const double& x, const double& z, const double& p2 );

    double getW4nodelta( const double& x, const double& z, const double& p2 );

    double getW5nodelta( const double& x, const double& z, const double& p2 );

    double getW1delta( const double& x, const double& z );

    double getW4plus5delta( const double& x, const double& z );

  private:
    // Friends

    // Data members

    double _alphas;
    double _epsilon1;
    double _epsilon2;
    double _epsilon3;
};

#endif    // EVTVUBDGAMMA_HH