FermionSpinInfo.h

// -*- C++ -*-
//
// FermionSpinInfo.h is a part of ThePEG - Toolkit for HEP Event Generation
// Copyright (C) 2003-2019 Peter Richardson, Leif Lonnblad
//
// ThePEG is licenced under version 3 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
#ifndef ThePEG_FermionSpinInfo_H
#define ThePEG_FermionSpinInfo_H
// This is the declaration of the FermionSpinInfo class.

#include "ThePEG/EventRecord/SpinInfo.h"
#include "ThePEG/Helicity/LorentzSpinor.h"
#include "FermionSpinInfo.fh"
#include <array>

namespace ThePEG {
namespace Helicity {

class FermionSpinInfo: public SpinInfo {

public:

  FermionSpinInfo()
    : SpinInfo(PDT::Spin1Half), _decaycalc(false) {}

  FermionSpinInfo(const Lorentz5Momentum & p, bool time)
    : SpinInfo(PDT::Spin1Half, p, time), _decaycalc(false) {}

public:

  void setBasisState(unsigned int hel,
                     const LorentzSpinor<SqrtEnergy> & in) const {
    assert(hel<2);
    _productionstates[hel] = in;
    _currentstates   [hel] = in;
  }

  void setDecayState(unsigned int hel,
                     const LorentzSpinor<SqrtEnergy> & in) const {
    assert(hel<2);
    _decaycalc = true;
    _decaystates[hel] = in;
  }

  const LorentzSpinor<SqrtEnergy> & getProductionBasisState(unsigned int hel) const {
    assert(hel<2);
    return _productionstates[hel];
  }

  const LorentzSpinor<SqrtEnergy> & getCurrentBasisState(unsigned int hel) const {
    assert(hel<2);
    return _currentstates[hel];
  }

  const LorentzSpinor<SqrtEnergy> & getDecayBasisState(unsigned int hel) const {
    assert(hel<2);
    if(!_decaycalc) {
      for(unsigned int ix=0;ix<2;++ix) _decaystates[ix]=_currentstates[ix];
      _decaycalc=true;
    }
    return _decaystates[hel];
  }

  virtual void transform(const LorentzMomentum &,const LorentzRotation &);

  virtual void undecay() const {
    _decaycalc=false;
    SpinInfo::undecay();
  }

  virtual void reset() {
    undecay();
    _currentstates = _productionstates;
    SpinInfo::reset();
  }

public:

  static void Init();

  virtual EIPtr clone() const;

private:

  FermionSpinInfo & operator=(const FermionSpinInfo &) = delete;

private:

  mutable std::array<LorentzSpinor<SqrtEnergy>,2> _productionstates;

  mutable std::array<LorentzSpinor<SqrtEnergy>,2> _currentstates;

  mutable std::array<LorentzSpinor<SqrtEnergy>,2> _decaystates;

  mutable bool _decaycalc;

};

}
}

namespace ThePEG {

}
#endif /* ThePEG_FermionSpinInfo_H */