TensorSpinInfo.h

// -*- C++ -*-
//
// TensorSpinInfo.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_TensorSpinInfo_H
#define THEPEG_TensorSpinInfo_H
// This is the declaration of the TensorSpinInfo class.

#include "ThePEG/EventRecord/SpinInfo.h"
#include "ThePEG/Helicity/LorentzTensor.h"
#include "TensorSpinInfo.fh"
// #include "TensorSpinInfo.xh"
#include <array>

namespace ThePEG {
namespace Helicity {

class TensorSpinInfo: public SpinInfo {

public:

  TensorSpinInfo() : SpinInfo(PDT::Spin2), _decaycalc(false) {}
  
  TensorSpinInfo(const Lorentz5Momentum & p, bool time)
    : SpinInfo(PDT::Spin2, p, time), _decaycalc(false) {}

public:

  void setBasisState(unsigned int hel, LorentzTensor<double> in) const {
    assert(hel<5);
    _productionstates[hel]=in;
    _currentstates   [hel]=in;
  }

  void setDecayState(unsigned int hel, LorentzTensor<double> in) const {
    assert(hel<5);
    _decaycalc = true;
    _decaystates[hel] = in;
  }

  const LorentzTensor<double> & getProductionBasisState(unsigned int hel) const {
    assert(hel<5);
    return _productionstates[hel];
  }
  
  const LorentzTensor<double> & getCurrentBasisState(unsigned int hel) const {
    assert(hel<5);
    return _currentstates[hel];
  }

  const LorentzTensor<double> & getDecayBasisState(unsigned int hel) const {
    assert(hel<5);
    if(!_decaycalc) {
      for(unsigned int ix=0;ix<5;++ix)
        _decaystates[ix]=_currentstates[ix].conjugate();
      _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:

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

private:

  mutable std::array<LorentzTensor<double>,5> _productionstates;

  mutable std::array<LorentzTensor<double>,5> _decaystates;

  mutable std::array<LorentzTensor<double>,5> _currentstates;

  mutable bool _decaycalc;

};

}
}


namespace ThePEG {

}
#endif /* THEPEG_TensorSpinInfo_H */