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D0_2009_S8202443

$Z/\gamma^*$ + jet + $X$ cross sections differential in pT(jet 1,2,3)
Experiment: D0 (Tevatron Run 2)
Inspire ID: 815094
Status: VALIDATED
Authors:
  • Frank Siegert
References: Beams: p- p+
Beam energies: (980.0, 980.0) GeV
Run details:
  • $p \bar{p} \to e^+ e^-$ + jets at 1960 GeV. Needs mass cut on lepton pair to avoid photon singularity, looser than $65 < m_{ee} < 115$ GeV.

Cross sections as a function of pT of the three leading jets in $Z/\gamma^{*} (\to e^{+} e^{-})$ + jet + X production in $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV, based on an integrated luminosity of 1.0 fb$^{-1}$.

Source code: D0_2009_S8202443.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/ZFinder.hh"
  5#include "Rivet/Projections/FastJets.hh"
  6
  7namespace Rivet {
  8
  9
 10  /// D0 Z + jet + \f$ X \f$ cross-section / \f$ p_\perp \f$ distributions
 11  class D0_2009_S8202443 : public Analysis {
 12  public:
 13
 14    RIVET_DEFAULT_ANALYSIS_CTOR(D0_2009_S8202443);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms
 21    void init() {
 22      FinalState fs;
 23      // Leptons in constrained tracking acceptance
 24      Cut cuts = (Cuts::abseta < 1.1 || Cuts::absetaIn(1.5, 2.5)) && Cuts::pT > 25*GeV;
 25      ZFinder zfinder_constrained(fs, cuts, PID::ELECTRON, 65*GeV, 115*GeV, 0.2, ZFinder::ClusterPhotons::NODECAY, ZFinder::AddPhotons::YES);
 26      declare(zfinder_constrained, "ZFinderConstrained");
 27      FastJets conefinder_constrained(zfinder_constrained.remainingFinalState(), FastJets::D0ILCONE, 0.5);
 28      declare(conefinder_constrained, "ConeFinderConstrained");
 29
 30      // Unconstrained leptons
 31      ZFinder zfinder(fs, Cuts::open(), PID::ELECTRON, 65*GeV, 115*GeV, 0.2, ZFinder::ClusterPhotons::NODECAY, ZFinder::AddPhotons::YES);
 32      declare(zfinder, "ZFinder");
 33      FastJets conefinder(zfinder.remainingFinalState(), FastJets::D0ILCONE, 0.5);
 34      declare(conefinder, "ConeFinder");
 35
 36      book(_h_jet1_pT_constrained ,1, 1, 1);
 37      book(_h_jet2_pT_constrained ,3, 1, 1);
 38      book(_h_jet3_pT_constrained ,5, 1, 1);
 39      book(_h_jet1_pT ,2, 1, 1);
 40      book(_h_jet2_pT ,4, 1, 1);
 41      book(_h_jet3_pT ,6, 1, 1);
 42
 43      book(_sum_of_weights,"sum_of_weights");
 44      book(_sum_of_weights_constrained, "sum_of_weights_constrained");
 45    }
 46
 47
 48    // Do the analysis
 49    void analyze(const Event& e) {
 50      // Unconstrained electrons
 51      const ZFinder& zfinder = apply<ZFinder>(e, "ZFinder");
 52      if (zfinder.bosons().size() == 0) {
 53        MSG_DEBUG("No unique lepton pair found.");
 54        vetoEvent;
 55      }
 56      _sum_of_weights->fill();
 57      const Jets jets_cut = apply<JetAlg>(e, "ConeFinder").jetsByPt(Cuts::pT > 20*GeV && Cuts::abseta < 2.5);
 58      if (jets_cut.size() > 0)
 59        _h_jet1_pT->fill(jets_cut[0].pT()/GeV);
 60      if (jets_cut.size() > 1)
 61        _h_jet2_pT->fill(jets_cut[1].pT()/GeV);
 62      if (jets_cut.size() > 2)
 63        _h_jet3_pT->fill(jets_cut[2].pT()/GeV);
 64
 65
 66      // Constrained electrons
 67      const ZFinder& zfinder_constrained = apply<ZFinder>(e, "ZFinderConstrained");
 68      if (zfinder_constrained.bosons().size() == 0) {
 69        MSG_DEBUG("No unique constrained lepton pair found.");
 70        return; // Not really a "veto", since if we got this far there is an unconstrained Z
 71      }
 72      _sum_of_weights_constrained->fill();
 73      const Jets& jets_constrained = apply<JetAlg>(e, "ConeFinderConstrained").jetsByPt(20*GeV);
 74      /// @todo Replace this explicit selection with a Cut
 75      Jets jets_cut_constrained;
 76      for (const Jet& j : jets_constrained) {
 77        if (j.abseta() < 2.5) jets_cut_constrained.push_back(j);
 78      }
 79      if (jets_cut_constrained.size() > 0)
 80        _h_jet1_pT_constrained->fill(jets_cut_constrained[0].pT()/GeV);
 81      if (jets_cut_constrained.size() > 1)
 82        _h_jet2_pT_constrained->fill(jets_cut_constrained[1].pT()/GeV);
 83      if (jets_cut_constrained.size() > 2)
 84        _h_jet3_pT_constrained->fill(jets_cut_constrained[2].pT()/GeV);
 85    }
 86
 87
 88    // Finalize
 89    void finalize() {
 90      scale(_h_jet1_pT, 1/ *_sum_of_weights);
 91      scale(_h_jet2_pT, 1/ *_sum_of_weights);
 92      scale(_h_jet3_pT, 1/ *_sum_of_weights);
 93      scale(_h_jet1_pT_constrained, 1/ *_sum_of_weights_constrained);
 94      scale(_h_jet2_pT_constrained, 1/ *_sum_of_weights_constrained);
 95      scale(_h_jet3_pT_constrained, 1/ *_sum_of_weights_constrained);
 96    }
 97
 98    /// @}
 99
100
101  private:
102
103    /// @name Histograms
104    /// @{
105    Histo1DPtr _h_jet1_pT;
106    Histo1DPtr _h_jet2_pT;
107    Histo1DPtr _h_jet3_pT;
108    Histo1DPtr _h_jet1_pT_constrained;
109    Histo1DPtr _h_jet2_pT_constrained;
110    Histo1DPtr _h_jet3_pT_constrained;
111    /// @}
112
113    CounterPtr _sum_of_weights, _sum_of_weights_constrained;
114
115  };
116
117
118
119  RIVET_DECLARE_ALIASED_PLUGIN(D0_2009_S8202443, D0_2009_I815094);
120
121}