DalitzSigma.h

// -*- C++ -*-
#ifndef Herwig_DalitzSigma_H
#define Herwig_DalitzSigma_H
//
// This is the declaration of the DalitzSigma class.
//
 
#include "DalitzResonance.h"
 
namespace Herwig {
 
using namespace ThePEG;
 
class DalitzSigma: public DalitzResonance {
 
public:
 
  DalitzSigma()
  {}
 
  DalitzSigma(long pid, ResonanceType::Type rtype, Energy m, Energy w,
              unsigned int d1, unsigned int d2, unsigned int s,
              double mag, double phi, InvEnergy rr,
              Energy2 a, Energy b1, InvEnergy b2, Energy g4pi)
    : DalitzResonance(pid,rtype,m,w,d1,d2,s,mag,phi,rr),
      a_(a), b1_(b1),b2_(b2), g4Pi_(g4pi)
  {}
 
public:
 
  virtual Complex BreitWigner(const Energy & mAB, const Energy & mA, const Energy & mB) const;
 
  virtual void dataBaseOutput(ofstream & output);
 
public:
 
  void persistentOutput(PersistentOStream & os) const;
 
  void persistentInput(PersistentIStream & is, int version);
 
  static void Init();
 
private:
 
  DalitzSigma & operator=(const DalitzSigma &) = delete;
 
private :
 
  double rho4pi(const Energy2 &s,const Energy & mpi) const {
    static const InvEnergy2 c1(3.5/GeV2);
    static const Energy2    c2(2.8*GeV2);
    return sqrt(1.-16.*sqr(mpi)/s)/(1.+exp(c1*(c2-s)));
  }
  
private:
 
  Energy2 a_;
 
  Energy b1_;
 
  InvEnergy b2_;
 
  Energy g4Pi_;
  
};
 
}
 
#endif /* Herwig_DalitzSigma_H */