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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
namespace Rivet {
/// @brief MC validation analysis for isolated di-photon events
class MC_DIPHOTON : public Analysis {
public:
/// Constructor
MC_DIPHOTON()
: Analysis("MC_DIPHOTON")
{ }
/// @name Analysis methods
//@{
void init() {
FinalState fs;
declare(fs, "FS");
IdentifiedFinalState ifs(Cuts::abseta < 2 && Cuts::pT > 20*GeV);
ifs.acceptId(PID::PHOTON);
declare(ifs, "IFS");
book(_h_m_PP ,"m_PP", logspace(50, 1.0, 0.25*(sqrtS()>0.?sqrtS():14000.)));
book(_h_pT_PP ,"pT_PP", logspace(50, 1.0, 0.25*(sqrtS()>0.?sqrtS():14000.)));
book(_h_pT_P1 ,"pT_P1", 50, 0.0, 70.0);
book(_h_pT_P2 ,"pT_P2", 50, 0.0, 70.0);
book(_h_dphi_PP ,"dphi_PP", 20, 0.0, M_PI);
}
void analyze(const Event& event) {
const double weight = 1.0;
const Particles& photons = apply<IdentifiedFinalState>(event, "IFS").particlesByPt();
if (photons.size() < 2) {
vetoEvent;
}
// Isolate photons with ET_sum in cone
Particles isolated_photons;
const Particles& fs = apply<FinalState>(event, "FS").particlesByPt();
for (const Particle& photon : photons) {
FourMomentum mom_in_cone;
double eta_P = photon.eta();
double phi_P = photon.phi();
for (const Particle& p : fs) {
if (deltaR(eta_P, phi_P, p.eta(), p.phi()) < 0.4) {
mom_in_cone += p.momentum();
}
}
if (mom_in_cone.Et()-photon.Et() < 4.0*GeV) {
isolated_photons.push_back(photon);
}
}
if (isolated_photons.size() != 2) {
vetoEvent;
}
_h_pT_P1->fill(isolated_photons[0].pT(), weight);
_h_pT_P2->fill(isolated_photons[1].pT(), weight);
FourMomentum mom_PP = isolated_photons[0].momentum() + isolated_photons[1].momentum();
_h_m_PP->fill(mom_PP.mass(), weight);
_h_pT_PP->fill(mom_PP.pT(), weight);
_h_dphi_PP->fill(deltaPhi(isolated_photons[0].phi(),
isolated_photons[1].phi()), weight);
}
void finalize() {
scale(_h_m_PP, crossSection()/sumOfWeights());
scale(_h_pT_PP, crossSection()/sumOfWeights());
scale(_h_pT_P1, crossSection()/sumOfWeights());
scale(_h_pT_P2, crossSection()/sumOfWeights());
scale(_h_dphi_PP, crossSection()/sumOfWeights());
}
//@}
private:
/// @name Histograms
//@{
Histo1DPtr _h_m_PP;
Histo1DPtr _h_pT_PP;
Histo1DPtr _h_pT_P1;
Histo1DPtr _h_pT_P2;
Histo1DPtr _h_dphi_PP;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(MC_DIPHOTON);
}
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