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Rivet analyses reference

MC_PHOTONKTSPLITTINGS

Monte Carlo validation observables for photon + jets production
Experiment: ()
Status: VALIDATED
Authors:
  • Frank Siegert
No references listed
Beams: * *
Beam energies: ANY
Run details:
  • Tevatron Run II ppbar -> gamma + jets.

Monte Carlo validation observables for photon + jets production

Source code: MC_PHOTONKTSPLITTINGS.cc
 1// -*- C++ -*-
 2#include "Rivet/Analyses/MC_KTSPLITTINGS_BASE.hh"
 3#include "Rivet/Projections/LeadingParticlesFinalState.hh"
 4#include "Rivet/Projections/VetoedFinalState.hh"
 5#include "Rivet/Projections/FastJets.hh"
 6
 7namespace Rivet {
 8
 9
10
11
12  /// @brief MC validation analysis for photon + jets events
13  class MC_PHOTONKTSPLITTINGS : public MC_KTSPLITTINGS_BASE {
14  public:
15
16    /// Default constructor
17    MC_PHOTONKTSPLITTINGS()
18      : MC_KTSPLITTINGS_BASE("MC_PHOTONKTSPLITTINGS", 4, "Jets")
19    {    }
20
21
22    /// @name Analysis methods
23    /// @{
24
25    /// Book histograms
26    void init() {
27      // General FS
28      FinalState fs((Cuts::etaIn(-5.0, 5.0)));
29      declare(fs, "FS");
30
31      // set photon cuts from input options
32      const double etacut = getOption<double>("ABSETAGAMMAX", 2.5);
33      const double ptcut = getOption<double>("PTGAMMIN", 30.);
34      
35      // Get leading photon
36      LeadingParticlesFinalState photonfs(FinalState(Cuts::abseta < etacut && Cuts::pT >= ptcut*GeV));
37      photonfs.addParticleId(PID::PHOTON);
38      declare(photonfs, "LeadingPhoton");
39
40      // FS for jets excludes the leading photon
41      VetoedFinalState vfs(fs);
42      vfs.addVetoOnThisFinalState(photonfs);
43      declare(vfs, "JetFS");
44
45      // set clustering radius from input option
46      const double R = getOption<double>("R", 0.6);
47
48      FastJets jetpro(vfs, JetAlg::KT, R);
49      declare(jetpro, "Jets");
50
51      MC_KTSPLITTINGS_BASE::init();
52    }
53
54
55    /// Do the analysis
56    void analyze(const Event& e) {
57      // Get the photon
58      const Particles photons = apply<FinalState>(e, "LeadingPhoton").particles();
59      if (photons.size() != 1) {
60        vetoEvent;
61      }
62      const FourMomentum photon = photons.front().momentum();
63
64      // Get all charged particles
65      const FinalState& fs = apply<FinalState>(e, "JetFS");
66      if (fs.empty()) {
67        vetoEvent;
68      }
69
70      // Isolate photon by ensuring that a 0.4 cone around it contains less than 7% of the photon's energy
71      const double egamma = photon.E();
72      double econe = 0.0;
73      for (const Particle& p : fs.particles()) {
74        if (deltaR(photon, p.momentum()) < 0.4) {
75          econe += p.E();
76          // Veto as soon as E_cone gets larger
77          if (econe/egamma > 0.07) {
78            vetoEvent;
79          }
80        }
81      }
82
83      MC_KTSPLITTINGS_BASE::analyze(e);
84    }
85
86
87    // Finalize
88    void finalize() {
89      MC_KTSPLITTINGS_BASE::finalize();
90    }
91
92    /// @}
93
94  };
95
96
97  RIVET_DECLARE_PLUGIN(MC_PHOTONKTSPLITTINGS);
98
99}