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Rivet analyses reference

MC_ZJETS

Monte Carlo validation observables for $Z[\ell^+ \, \ell^-]$ + jets production
Experiment: ()
Status: VALIDATED
Authors:
  • Frank Siegert
  • Christian Gutschow
No references listed
Beams: * *
Beam energies: ANY
Run details:
  • $\ell^+ \ell^-$ + jets analysis. Needs mass cut on lepton pair to avoid photon singularity, e.g. a min range of $66 < m_{ll} < 116$ GeV

Available observables are the pT of jets 1-4, jet multiplicity, $\Delta\eta(Z, \text{jet1})$, $\Delta R(\text{jet2}, \text{jet3})$, differential jet rates 0->1, 1->2, 2->3, 3->4, and integrated 0--4 jet rates.

Source code: MC_ZJETS.cc
 1// -*- C++ -*-
 2#include "Rivet/Analyses/MC_JetAnalysis.hh"
 3#include "Rivet/Projections/ZFinder.hh"
 4#include "Rivet/Projections/FastJets.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief MC validation analysis for Z + jets events
10  class MC_ZJETS : public MC_JetAnalysis {
11  public:
12
13    /// Default constructor
14    MC_ZJETS(string name = "MC_ZJETS")
15      : MC_JetAnalysis(name, 4, "Jets")
16	  {	  }
17
18
19    /// @name Analysis methods
20    //@{
21
22    /// Initialize
23    void init() {
24		  _dR=0.2;
25      if (getOption("SCHEME") == "BARE")  _dR = 0.0;
26		  _lepton=PID::ELECTRON;
27      if (getOption("LMODE") == "MU")  _lepton = PID::MUON;
28
29      FinalState fs;
30      Cut cut = Cuts::abseta < 3.5 && Cuts::pT > 25*GeV;
31      ZFinder zfinder(fs, cut, _lepton, 65*GeV, 115*GeV, _dR, ZFinder::ClusterPhotons::NODECAY, ZFinder::AddPhotons::YES);
32      declare(zfinder, "ZFinder");
33      FastJets jetpro(zfinder.remainingFinalState(), FastJets::ANTIKT, 0.4);
34      declare(jetpro, "Jets");
35
36      book(_h_Z_jet1_deta ,"Z_jet1_deta", 50, -5, 5);
37      book(_h_Z_jet1_dR ,"Z_jet1_dR", 25, 0.5, 7.0);
38
39      MC_JetAnalysis::init();
40    }
41
42
43
44    /// Do the analysis
45    void analyze(const Event & e) {
46      MSG_TRACE("MC_ZJETS: running ZFinder");
47      const ZFinder& zfinder = apply<ZFinder>(e, "ZFinder");
48      if (zfinder.bosons().size() != 1) vetoEvent;
49      const FourMomentum& zmom = zfinder.bosons()[0].momentum();
50      MSG_TRACE("MC_ZJETS: have exactly one Z boson candidate");
51
52      const Jets& jets = apply<FastJets>(e, "Jets").jetsByPt(_jetptcut);
53      if (jets.size() > 0) {
54        MSG_TRACE("MC_ZJETS: have at least one valid jet");
55        _h_Z_jet1_deta->fill(zmom.eta()-jets[0].eta());
56        _h_Z_jet1_dR->fill(deltaR(zmom, jets[0].momentum()));
57      }
58
59      MC_JetAnalysis::analyze(e);
60    }
61
62
63    /// Finalize
64    void finalize() {
65      scale(_h_Z_jet1_deta, crossSection()/picobarn/sumOfWeights());
66      scale(_h_Z_jet1_dR, crossSection()/picobarn/sumOfWeights());
67      MC_JetAnalysis::finalize();
68    }
69
70    //@}
71
72
73  protected:
74
75    /// @name Parameters for specialised e/mu and dressed/bare subclassing
76    //@{
77    double _dR;
78    PdgId _lepton;
79    //@}
80
81
82  private:
83
84    /// @name Histograms
85    //@{
86    Histo1DPtr _h_Z_jet1_deta;
87    Histo1DPtr _h_Z_jet1_dR;
88    //@}
89
90  };
91
92  // The hooks for the plugin system
93  RIVET_DECLARE_PLUGIN(MC_ZJETS);
94}