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// GEANT4 tag $Name: not supported by cvs2svn $
//
//
// GEANT4 physics class: G4QuasiElRatios -- header file
// M.V. Kossov, ITEP(Moscow), 24-OCT-01
// The last update: M.V. Kossov, CERN/ITEP (Moscow) 15-Oct-2006
// ----------------------------------------------------------------------
// This class has been extracted from the CHIPS model. 
// All the dependencies on CHIPS classes have been removed.
// Short description: Provides percentage of quasi-free and quasi-elastic
// reactions in the inelastic reactions.
// ----------------------------------------------------------------------

#ifndef G4QuasiElRatios_h
#define G4QuasiElRatios_h 1

#include "globals.hh"
#include "G4ios.hh"
#include "Randomize.hh"
#include <vector>
#include "G4ProtonElasticCrossSection.hh"
#include "G4NeutronElasticCrossSection.hh"
#include "G4LorentzVector.hh"


class G4QuasiElRatios
{
protected:
    
    G4QuasiElRatios();                 // Constructor
    
public:
    
    ~G4QuasiElRatios();                 // Destructor
    
    static G4QuasiElRatios* GetPointer(); // Gives a pointer to this singletone
    
    // Pair(QuasiFree/Inelastic,QuasiElastic/QuasiFree)
    std::pair<G4double,G4double> GetRatios(G4double pIU, G4int prPDG, G4int tgZ, G4int tgN);
    // ChargeExchange/QuasiElastic factor pair<for protons (Z), for neutrons(N)>
    std::pair<G4double,G4double> GetChExFactor(G4double pIU, G4int pPDG, G4int Z, G4int N);
    // scatter (pPDG,p4M) on a virtual nucleon (NPDG,N4M), result: final pair(newN4M,newp4M)
    // if(newN4M.e()==0.) - below threshold, XS=0, no scattering of the projectile happened
    std::pair<G4LorentzVector,G4LorentzVector> Scatter(G4int NPDG, G4LorentzVector N4M,
                                                       G4int pPDG, G4LorentzVector p4M);
    // ChExer (pPDG,p4M) on a virtual nucleon (NPDG,N4M), result: final pair(newN4M,newp4M)
    // if(newN4M.e()==0.) - keep projectile, XS=0, no interaction of the progectile happened
    // User should himself change the charge (PDG) (e.g. pn->np, pi+n->pi0p, pi-p->pi0n etc.)
    // Recepy: change target n to p or taget p to n and conserve enrgy, changing projectile
    // Do not use for the nucleon, as it is already included in quasielastic, and for pi0.
    std::pair<G4LorentzVector,G4LorentzVector> ChExer(G4int NPDG, G4LorentzVector N4M,
                                                      G4int pPDG, G4LorentzVector p4M);
    // Mean hN El and Tot XS(IU) for the isotopic (Z,N): on p -> (Z=1,N=0), on n -> (Z=0,N=1)
    std::pair<G4double,G4double> GetElTot(G4double pIU, G4int hPDG, G4int Z, G4int N); //(IU)
    
    // Calculate ChEx/El ratio coefficient (p is in independent units, (Z,N) is a target)
    G4double ChExElCoef(G4double p, G4int Z, G4int N, G4int pPDG);
    
    // For hadron PDG with momentum Mom (GeV/c) on F(p/n) calculate <sig_el,sig_tot> pair(mb)
    // F=true corresponds to the Nroton target, F=false corresponds to the Proton target
    std::pair<G4double,G4double> GetElTotXS(G4double Mom, G4int PDG, G4bool F);//<sigEl,sigT>
    std::pair<G4double,G4double> FetchElTot(G4double pGeV,G4int PDG,G4bool F);//<E,T>fromAMDB
    
    G4bool RelDecayIn2(G4LorentzVector& theMomentum, G4LorentzVector& f4Mom, 
                       G4LorentzVector& s4Mom, G4LorentzVector& dir,
                       G4double maxCost = 1., G4double minCost = -1.);
    
private:
    // These working member functions are in CHIPS units and must not be used externally
    G4double GetQF2IN_Ratio(G4double TotCS_mb, G4int A); // QuasiFree/Inelastic (fast)
    G4double CalcQF2IN_Ratio(G4double TCSmb, G4int A); // R=QuasuFree/Inelastic (sig_t in mb)
    std::pair<G4double,G4double> CalcElTot(G4double pGeV,G4int Index);//(sigEl,sigTot)(Index)
    
    // Body
private:
    static std::vector<G4double*> vT;     // Vector of pointers to LinTable
    static std::vector<G4double*> vL;     // Vector of pointers to LogTable
    static std::vector<std::pair<G4double,G4double>*> vX; // Vector of ETPointers to LogTable
};
#endif