Rivet analyses

title: CMS_2012_I1102908

Measurement of inclusive and exclusive dijet production ratio at large rapidity intervals at center-of-mass energy 7 TeV.

Experiment: CMS (LHC)

Inspire ID: 1102908

Status: VALIDATED

Authors: - Grzegorz Brona - Vladimir Gavrilov - Hannes Jung - Victor Kim - Victor Murzin - Vadim Oreshkin - Grigory Pivovarov - Ivan Pozdnyakov - Grigory Safronov

References: - Expt page: CMS-FWD-10-014 - CERN-PH-EP-2012-088 - arXiv: 1204.0696 - Submitted to the EPJ C

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - Inclusive QCD at 7TeV comEnergy, ptHat (or equivalent) greater than 15 GeV

This is a measurement of the ratio of inclusive to exclusive dijet production as a function of the absolute distance in rapidity, $\Delta y$, between jets. The ratio of the Mueller-Navelet to exclusive dijet production is also measured. These measurements were performed with the CMS detector in proton-proton collisions at $\sqrt{s} = 7$ TeV for jets with $p_T > 35$ GeV and $|y| < 4.7$ taken from a mixture of two data samples, one of which containing dijets with moderate rapidity separation and the other containing dijets with large rapidity separation, with integrated luminosity of 33/nb and 5/pb respectively. The measured observables are corrected for detector effects.

Source code:CMS_2012_I1102908.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include

namespace Rivet {

/// @brief CMS inclusive and exclusive dijet production ratio at large rapidity intervals class CMS_2012_I1102908 : public Analysis { public:

CMS_2012_I1102908()
    : Analysis("CMS_2012_I1102908") { }


void init() {
  // Projections
  declare(FastJets(FinalState(), JetAlg::ANTIKT, 0.5), "antikT");

  // Histograms
  /// @todo Can we manage to only register these as they are "really" created in the finalize()?
  book(_h_dijet_ratio, 1, 1, 1);
  book(_h_MN_dijet_ratio, 2, 1, 1);

  // Temporary histograms (directly instantiated)
  book(_h_DeltaY_exclusive, "TMP/excl", refData(1, 1, 1));
  book(_h_DeltaY_inclusive, "TMP/incl", refData(1, 1, 1));
  book(_h_DeltaY_MN, "TMP/YMN", refData(1, 1, 1));
}


void analyze(const Event& event) {

  // Jets with  pT > 35.0, -4.7 < y < 4.7
  const JetFinder& jet_alg = apply<JetFinder>(event, "antikT");
  const Jets& jets = jet_alg.jets(Cuts::pT > 35 * GeV && Cuts::absrap < 4.7);

  // Veto event if number of jets less than 2
  if (jets.size() < 2) return;

  // Loop over jet pairs
  double deltaY_MN = 0.0;
  for (size_t ij1 = 0; ij1 < jets.size(); ++ij1) {
    for (size_t ij2 = ij1 + 1; ij2 < jets.size(); ++ij2) {
      const double deltaY = fabs(jets[ij1].rapidity() - jets[ij2].rapidity());
      // Exclusive dijet case:
      if (jets.size() == 2) _h_DeltaY_exclusive->fill(deltaY);
      // Inclusive jets case:
      _h_DeltaY_inclusive->fill(deltaY);
      // Mueller-Navelet:
      if (deltaY > deltaY_MN) deltaY_MN = deltaY;
    }
  }
  _h_DeltaY_MN->fill(deltaY_MN);
}


void finalize() {
  efficiency(_h_DeltaY_exclusive, _h_DeltaY_inclusive, _h_dijet_ratio);
  efficiency(_h_DeltaY_exclusive, _h_DeltaY_MN, _h_MN_dijet_ratio);
  transform(*_h_dijet_ratio, _invert);
  transform(*_h_MN_dijet_ratio, _invert);
}

private:

/// Reciprocal function with div-by-zero protection, for inverting the efficiency measure
static double _invert(double x) {
  return (x > 0) ? 1 / x : 0;
}

/// @name Histograms
/// @{
Estimate1DPtr _h_dijet_ratio, _h_MN_dijet_ratio;
Histo1DPtr _h_DeltaY_inclusive, _h_DeltaY_exclusive, _h_DeltaY_MN;
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2012_I1102908);

} ```