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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_JetSplittings.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_JetSplittings {
14  public:
15
16    /// Default constructor
17    MC_PHOTONKTSPLITTINGS()
18      : MC_JetSplittings("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      // Get leading photon
32      LeadingParticlesFinalState photonfs(FinalState(Cuts::abseta < 2.5 && Cuts::pT >= 30*GeV));
33      photonfs.addParticleId(PID::PHOTON);
34      declare(photonfs, "LeadingPhoton");
35
36      // FS for jets excludes the leading photon
37      VetoedFinalState vfs(fs);
38      vfs.addVetoOnThisFinalState(photonfs);
39      declare(vfs, "JetFS");
40      FastJets jetpro(vfs, FastJets::KT, 0.6);
41      declare(jetpro, "Jets");
42
43      MC_JetSplittings::init();
44    }
45
46
47    /// Do the analysis
48    void analyze(const Event& e) {
49      // Get the photon
50      const Particles photons = apply<FinalState>(e, "LeadingPhoton").particles();
51      if (photons.size() != 1) {
52        vetoEvent;
53      }
54      const FourMomentum photon = photons.front().momentum();
55
56      // Get all charged particles
57      const FinalState& fs = apply<FinalState>(e, "JetFS");
58      if (fs.empty()) {
59        vetoEvent;
60      }
61
62      // Isolate photon by ensuring that a 0.4 cone around it contains less than 7% of the photon's energy
63      const double egamma = photon.E();
64      double econe = 0.0;
65      for (const Particle& p : fs.particles()) {
66        if (deltaR(photon, p.momentum()) < 0.4) {
67          econe += p.E();
68          // Veto as soon as E_cone gets larger
69          if (econe/egamma > 0.07) {
70            vetoEvent;
71          }
72        }
73      }
74
75      MC_JetSplittings::analyze(e);
76    }
77
78
79    // Finalize
80    void finalize() {
81      MC_JetSplittings::finalize();
82    }
83
84    //@}
85
86  };
87
88
89
90  // The hook for the plugin system
91  RIVET_DECLARE_PLUGIN(MC_PHOTONKTSPLITTINGS);
92
93}