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// $Id$
//
//
// G4 Model: Low energy elastic scattering -- header file
// F.W. Jones, TRIUMF, 04-JUN-96
//  
// For further comments see G4LElastic.cc.
//
// use -scheme for elastic scattering: HPW, 20th June 1997
// most of the code comes from the old Low-energy Elastic class

#ifndef G4LElastic_h
#define G4LElastic_h 1
 
// Class Description
// Final state production model for hadron nuclear elastic scattering; 
// To be used in your physics list in case you need this physics.
// In this case you want to register an object of this class with 
// the corresponding process.
// Class Description - End

#include "globals.hh"
#include "Randomize.hh"
#include "G4Element.hh"
#include "G4ElementVector.hh"
#include "G4ElementTable.hh"
#include "G4PhysicsTable.hh"
#include "G4PhysicsVector.hh"
#include "G4LPhysicsFreeVector.hh"
#include "G4LightMedia.hh"
#include "G4Step.hh"
#include "G4TrackStatus.hh"
#include "G4HadronicInteraction.hh"


class G4LElastic : public G4HadronicInteraction
{
  public:

    G4LElastic(const G4String& name = "G4LElastic");

    ~G4LElastic() {};
 
    G4HadFinalState* ApplyYourself(const G4HadProjectile& aTrack, 
                                   G4Nucleus& targetNucleus);

    virtual void ModelDescription(std::ostream& outFile) const;

    virtual const std::pair<G4double, G4double> GetFatalEnergyCheckLevels() const;

  private:

    G4LightMedia LightMedia;

    G4int Rtmi(G4double* x, G4double xli, G4double xri, G4double eps, 
               G4int iend,
               G4double aa, G4double bb, G4double cc, G4double dd, 
               G4double rr);

    G4double Fctcos(G4double t, 
                    G4double aa, G4double bb, G4double cc, G4double dd, 
                    G4double rr);

    void Defs1(G4double p, G4double px, G4double py, G4double pz, 
               G4double pxinc, G4double pyinc, G4double pzinc, 
               G4double* pxnew, G4double* pynew, G4double* pznew);
};
#endif