EvtWnPi.hh

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#ifndef EvtWNPI_HH
#define EvtWNPI_HH

#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtTensor4C.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenBase/EvtVector4R.hh"

// Description: Routine to calculate W -> (n pi) current
//                      according to [Kuhn, Was, Acta.Phys.Polon B39 (2008) 147]

class EvtWnPi {
  public:
    EvtVector4C WCurrent( EvtVector4R q1 );
    EvtVector4C WCurrent( EvtVector4R q1, EvtVector4R q2 );
    EvtVector4C WCurrent( EvtVector4R q1, EvtVector4R q2, EvtVector4R q3 );
    EvtVector4C WCurrent( EvtVector4R q1, EvtVector4R q2, EvtVector4R q3,
                          EvtVector4R q4, EvtVector4R q5 );

  protected:
    EvtVector4C JB( EvtVector4R q1, EvtVector4R q2, EvtVector4R q3,
                    EvtVector4R q4, EvtVector4R q5 );
    EvtComplex BWa( EvtVector4R q );
    EvtComplex BWf( EvtVector4R q );
    EvtComplex BWr( EvtVector4R q );
    double pi3G( double Q2 );
};

#endif