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//
// Geant4 class file
//
// File name:     G4PolarizedIonisationMollerXS
//
// Author:        Andreas Schaelicke
//
// Class Description:
//   * calculates the differential cross section
//     incoming electron (along positive z direction) scatters at an electron at
//     rest
//   * phi denotes the angle between the scattering plane (defined by the
//     outgoing electron) and X-axis
//   * all stokes vectors refer to spins in the Global System (X,Y,Z)

#ifndef G4PolarizedIonisationMollerXS_h
#define G4PolarizedIonisationMollerXS_h 1

#include "G4StokesVector.hh"
#include "G4VPolarizedXS.hh"

class G4PolarizedIonisationMollerXS : public G4VPolarizedXS
{
 public:
  G4PolarizedIonisationMollerXS();
  ~G4PolarizedIonisationMollerXS() override;

  void Initialize(G4double x, G4double y, G4double phi,
                  const G4StokesVector& p0, const G4StokesVector& p1,
                  G4int flag = 0) override;

  G4double XSection(const G4StokesVector& pol2,
                    const G4StokesVector& pol3) override;

  G4double TotalXSection(G4double xmin, G4double xmax, G4double y,
                         const G4StokesVector& pol0,
                         const G4StokesVector& pol1) override;

  // return expected mean polarisation
  G4StokesVector GetPol2() override;
  G4StokesVector GetPol3() override;

  G4PolarizedIonisationMollerXS& operator                             =(
    const G4PolarizedIonisationMollerXS& right) = delete;
  G4PolarizedIonisationMollerXS(const G4PolarizedIonisationMollerXS&) = delete;

 private:
  // - part depending on the polarization of the final photon
  G4ThreeVector fPhi2;
  // - part depending on the polarization of the final electron
  G4ThreeVector fPhi3;

  G4double fPhi0;
};
#endif