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// $Id$

#ifndef G4SingleDiffractiveExcitation_h
#define G4SingleDiffractiveExcitation_h 1
// ------------------------------------------------------------
//      GEANT 4 class header file
//
//      ---------------- G4SingleDiffractiveExcitation --------------
//             by Gunter Folger, October 1998.
//      diffractive Excitation used by strings models
//	Take a projectile and a target
//	excite the projectile and target
// ------------------------------------------------------------

#include <CLHEP/Units/SystemOfUnits.h>

#include "globals.hh"
#include "G4ThreeVector.hh"
#include "G4QGSDiffractiveExcitation.hh"

class G4VSplitableHadron;
class G4ExcitedString;

class G4SingleDiffractiveExcitation : public G4QGSDiffractiveExcitation
{

public:

	G4SingleDiffractiveExcitation(G4double sigmaPt=0.6*CLHEP::GeV,
                                      G4double minExtraMass=250*CLHEP::MeV,
                                      G4double x0mass=250*CLHEP::MeV);
	~G4SingleDiffractiveExcitation();

	G4bool ExciteParticipants (G4VSplitableHadron *aPartner, G4VSplitableHadron * bPartner) const;

	//      void SetPtWidth(G4double aValue) { widthOfPtSquare = aValue*aValue; }
	//      void SetExtraMass(G4double aValue) { minExtraMass = aValue; }
	//      void SetMinimumMass(G4double aValue) { minmass = aValue; }


private:

	G4SingleDiffractiveExcitation(const G4SingleDiffractiveExcitation &right);

	G4double ChooseX(G4double Xmin, G4double Xmax) const;
	G4ThreeVector GaussianPt(G4double widthSquare, G4double maxPtSquare) const;

	const G4SingleDiffractiveExcitation & operator=(const G4SingleDiffractiveExcitation &right);
	int operator==(const G4SingleDiffractiveExcitation &right) const;
	int operator!=(const G4SingleDiffractiveExcitation &right) const;

private:
	// Model Parameters:
	const G4double widthOfPtSquare;	// width^2 of pt for string excitation
	const G4double minExtraMass;	// minimum excitation mass 
	const G4double minmass;	// mean pion transverse mass; used for Xmin 
};

#endif