Rivet analyses

Dijet angular distributions

Experiment: CDF (Tevatron Run 1)

Inspire ID: 423414

Status: VALIDATED

Authors: - Frank Siegert

References: - Phys.Rev.Lett.77:5336-5341,1996 - DOI: 10.1103/PhysRevLett.77.5336 - arXiv: hep-ex/9609011

Beams: p- p+

Beam energies: (900.0, 900.0)GeV

Run details: - QCD dijet events at Tevatron $\sqrt{s}=1.8$ TeV without MPI.

Measurement of jet angular distributions in events with two jets in the final state in 5 bins of dijet invariant mass. Based on 106pb−1

Source code:CDF_1996_I423414.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"

namespace Rivet {


  /// @brief CDF dijet angular distributions
  class CDF_1996_I423414 : public Analysis {
  public:

    RIVET_DEFAULT_ANALYSIS_CTOR(CDF_1996_I423414);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      FinalState fs(Cuts::abseta < 4.2);
      declare(FastJets(fs, JetAlg::CDFJETCLU, 0.7), "Jets");

      book(_h_chi, {241., 300., 400., 517., 625., 1800.},
                   {"d01-x01-y01", "d01-x01-y02", "d01-x01-y03", "d01-x01-y04", "d01-x01-y05"});
      book(_h_ratio,  2, 1, 1);
      book(_htmp_chi_above_25 ,"TMP/chiabove25", refData(2, 1, 1));
      book(_htmp_chi_below_25 ,"TMP/chibelow25", refData(2, 1, 1));
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      Jets jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > 50.0*GeV);
      if (jets.size() < 2) vetoEvent;

      const FourMomentum jet1 = jets[0].momentum();
      const FourMomentum jet2 = jets[1].momentum();
      const double eta1 = jet1.eta();
      const double eta2 = jet2.eta();
      const double chi = exp(fabs(eta1 - eta2));
      if (fabs(eta2) > 2.0 || fabs(eta1) > 2.0 || chi > 5.0) vetoEvent;

      double m = FourMomentum(jet1 + jet2).mass();
      _h_chi->fill(m, chi);

      // Fill ratio numerator or denominator depending on chi value
      ((chi > 2.5) ? _htmp_chi_above_25 : _htmp_chi_below_25)->fill(m/GeV);
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h_chi);
      divide(_htmp_chi_below_25, _htmp_chi_above_25, _h_ratio);
    }

    /// @}


  private:

    /// @name Histograms
    /// @{
    Histo1DGroupPtr _h_chi;
    Histo1DPtr _htmp_chi_above_25, _htmp_chi_below_25;
    Estimate1DPtr _h_ratio;
    /// @}

  };



  RIVET_DECLARE_ALIASED_PLUGIN(CDF_1996_I423414, CDF_1996_S3418421);

}

Aliases: - CDF_1996_S3418421