Rivet analyses

title: CDF_1996_I423414

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 $106 \mathrm{pb}^{-1}$

Source code:CDF_1996_I423414.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.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