PEtaDoubleDalitzFF.cc

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//Eta double Dalitz decay form factor
//
//References: ???
//
//                             Author:  I. Froehlich
//                             Written: 17.9.2009
//
 
 
#include "PEtaDoubleDalitzFF.h"
 
 
PDistribution *PEtaDoubleDalitzFF::Clone(const char*) const {
    //clone the object
    return new PEtaDoubleDalitzFF((const PEtaDoubleDalitzFF &)* this);
};
 
PEtaDoubleDalitzFF::PEtaDoubleDalitzFF(Char_t *id, Char_t *de, Int_t key) :
    PChannelModel(id, de, key) {
    //Constructor
    Lambda = 0.770; //default value
    dil1 = dil2 = parent = NULL;
};
 
Bool_t PEtaDoubleDalitzFF::Init(void) {
 
    parent = GetParticle("parent");
    if (!parent) {
    Warning("Init", "Parent not found");
    return kFALSE;
    }
 
    dil1 = GetParticle("dilepton");
    dil2 = GetParticle("dilepton");
 
    if (!dil1 || !dil2) {
    Warning("Init","Dileptons not found");
    return kFALSE;
    }
 
    EnableWeighting();
    SetExpectedWeightMean(-1);
 
    return kTRUE;
}
 
Double_t PEtaDoubleDalitzFF::GetWeight() {
 
    TLorentzVector *P3, *P4;
    P3 = (TLorentzVector*) dil1;
    P4 = (TLorentzVector*) dil2;
 
 
    //*******************    Extraction of physics observables      ****************
    Double_t q1_2 = (*P3)*(*P3);//Lorentz Vector of 1st g squared
    Double_t q2_2 = (*P4)*(*P4);//Lorentz Vector of 2nd g squared
    //*************FF from Johan and Fredrik paper***********************
    //     Double_t FF=Lambda^4/(Lambda^2+mVV[0])*Lambda/(Lambda^2+mVV[1]);// including process with Lambda parameter - Ro meson
    //     Double_t FF=Lambda*Lambda*Lambda*Lambda/((Lambda*Lambda-q1_2)*(Lambda*Lambda-q2_2));
 
    //            Double_t FF=Lambda*Lambda/((Lambda*Lambda-q1_2));
    Double_t FF = Lambda*Lambda*Lambda*Lambda/((Lambda*Lambda-q1_2)*(Lambda*Lambda-q2_2));
    float weightFF = FF;
 
    //weightFF = 20;
    //  cout << weightFF << endl;
    return weightFF;
}
 
 
ClassImp(PEtaDoubleDalitzFF)