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D0_2004_S5992206

Run II jet azimuthal decorrelation analysis
Experiment: D0 (Tevatron Run 2)
Inspire ID: 659398
Status: VALIDATED
Authors:
  • Lars Sonnenschein
References: Beams: p- p+
Beam energies: (980.0, 980.0) GeV
Run details:
  • QCD events in ppbar interactions at $\sqrt{s} = 1960$ GeV.

Correlations in the azimuthal angle between the two largest pT jets have been measured using the D0 detector in ppbar collisions at 1960 GeV. The analysis is based on an inclusive dijet event sample in the central rapidity region. The correlations are determined for four different pT intervals.

Source code: D0_2004_S5992206.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FastJets.hh"
  4#include "Rivet/Projections/VetoedFinalState.hh"
  5#include "Rivet/Projections/VisibleFinalState.hh"
  6#include "Rivet/Projections/MissingMomentum.hh"
  7
  8namespace Rivet {
  9
 10
 11  /// @brief D0 Run II angular correlations in di-jet events
 12  /// @author Lars Sonnenschein
 13  ///
 14  /// Measurement of angular correlations in di-jet events.
 15  ///
 16  /// @par Run conditions
 17  /// @arg \f$ \sqrt{s} = \f$ 1960 GeV
 18  /// @arg Run with generic QCD events.
 19  /// @arg Several \f$ p_\perp^\text{min} \f$ cutoffs are probably required to fill the histograms:
 20  /// @arg \f$ p_\perp^\text{min} = \f$ 50, 75, 100, 150 GeV for the four pT ranges respecively
 21  ///
 22  class D0_2004_S5992206 : public Analysis {
 23  public:
 24
 25    RIVET_DEFAULT_ANALYSIS_CTOR(D0_2004_S5992206);
 26
 27
 28    /// @name Analysis methods
 29    /// @{
 30
 31    void init() {
 32      // Final state for jets, mET etc.
 33      const FinalState fs((Cuts::etaIn(-3.0, 3.0)));
 34      declare(fs, "FS");
 35      // Veto neutrinos, and muons with pT above 1.0 GeV
 36      VetoedFinalState vfs(fs);
 37      vfs.vetoNeutrinos();
 38      vfs.addVetoPairDetail(PID::MUON, 1.0*GeV, DBL_MAX);
 39      declare(vfs, "VFS");
 40      declare(FastJets(vfs, FastJets::D0ILCONE, 0.7), "Jets");
 41      declare(MissingMomentum(vfs), "CalMET");
 42
 43      // Book histograms
 44      book(_histJetAzimuth_pTmax75_100  ,1, 2, 1);
 45      book(_histJetAzimuth_pTmax100_130 ,2, 2, 1);
 46      book(_histJetAzimuth_pTmax130_180 ,3, 2, 1);
 47      book(_histJetAzimuth_pTmax180_    ,4, 2, 1);
 48    }
 49
 50
 51    /// Do the analysis
 52    void analyze(const Event& event) {
 53
 54      // Analyse and print some info
 55      const JetAlg& jetpro = apply<JetAlg>(event, "Jets");
 56      MSG_DEBUG("Jet multiplicity before any pT cut = " << jetpro.size());
 57
 58      const Jets jets  = jetpro.jetsByPt(40.0*GeV);
 59      if (jets.size() >= 2) {
 60        MSG_DEBUG("Jet multiplicity after pT > 40 GeV cut = " << jets.size());
 61      } else {
 62        vetoEvent;
 63      }
 64      const double rap1 = jets[0].rapidity();
 65      const double rap2 = jets[1].rapidity();
 66      if (fabs(rap1) > 0.5 || fabs(rap2) > 0.5) {
 67        vetoEvent;
 68      }
 69      MSG_DEBUG("Jet eta and pT requirements fulfilled");
 70      const double pT1 = jets[0].pT();
 71
 72      const MissingMomentum& caloMissEt = apply<MissingMomentum>(event, "CalMET");
 73      MSG_DEBUG("Missing vector Et = " << caloMissEt.vectorEt()/GeV << " GeV");
 74      if (caloMissEt.vectorEt().mod() > 0.7*pT1) {
 75        MSG_DEBUG("Vetoing event with too much missing ET: "
 76                  << caloMissEt.vectorEt()/GeV << " GeV > "
 77                  << 0.7*pT1/GeV << " GeV");
 78        vetoEvent;
 79      }
 80
 81      if (pT1/GeV >= 75.0) {
 82        const double dphi = deltaPhi(jets[0].phi(), jets[1].phi());
 83        if (inRange(pT1/GeV, 75.0, 100.0)) {
 84          _histJetAzimuth_pTmax75_100->fill(dphi);
 85        } else if (inRange(pT1/GeV, 100.0, 130.0)) {
 86          _histJetAzimuth_pTmax100_130->fill(dphi);
 87        } else if (inRange(pT1/GeV, 130.0, 180.0)) {
 88          _histJetAzimuth_pTmax130_180->fill(dphi);
 89        } else if (pT1/GeV > 180.0) {
 90          _histJetAzimuth_pTmax180_->fill(dphi);
 91        }
 92      }
 93
 94    }
 95
 96
 97    // Finalize
 98    void finalize() {
 99      // Normalize histograms to unit area
100      normalize(_histJetAzimuth_pTmax75_100);
101      normalize(_histJetAzimuth_pTmax100_130);
102      normalize(_histJetAzimuth_pTmax130_180);
103      normalize(_histJetAzimuth_pTmax180_);
104    }
105
106    /// @}
107
108
109  private:
110
111    /// @name Histograms
112    /// @{
113    Histo1DPtr _histJetAzimuth_pTmax75_100;
114    Histo1DPtr _histJetAzimuth_pTmax100_130;
115    Histo1DPtr _histJetAzimuth_pTmax130_180;
116    Histo1DPtr _histJetAzimuth_pTmax180_;
117    /// @}
118
119  };
120
121
122
123  RIVET_DECLARE_ALIASED_PLUGIN(D0_2004_S5992206, D0_2004_I659398);
124
125}