Rivet analyses

title: CMS_2013_I1208923

Jet-pT and dijet mass at sqrt(s) = 7 TeV

Experiment: CMS (LHC)

Inspire ID: 1208923

Status: VALIDATED

Authors: - Markus Radziej - Samatha Dooling

References: none listed

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - Hard QCD process with a flat pT spectrum is recommended.

The single jet differential cross section has been measured as a function of the jet momentum and the dijet differential cross section as a function of the dijet mass. The data has been recorded by the CMS detector at the center of mass energy of 7 TeV. To reconstruct the jets, the anti-$k_T$ algorithm with a cone radius of $R = 0.7$ (AK7) has been used. The results are split into five rapidity bins, ranging from 0.0 to 2.5 with a width of 0.5 each.

Source code:CMS_2013_I1208923.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

// This analysis is a derived from the class Analysis: class CMS_2013_I1208923 : public Analysis {

public:

// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2013_I1208923);

// Book histograms and initialize projections:
void init() {
  const FinalState fs;
  declare(fs, "FS");

  // Initialize the projections
  declare(FastJets(fs, JetAlg::ANTIKT, 0.7), "Jets");

  // Book histograms
  book(_h_sigma, {0., 0.5, 1., 1.5, 2., 2.5},
       {"d01-x01-y01", "d01-x01-y02", "d01-x01-y03", "d01-x01-y04", "d01-x01-y05"});
  book(_h_invMass, {0., 0.5, 1., 1.5, 2., 2.5},
       {"d02-x01-y01", "d02-x01-y02", "d02-x01-y03", "d02-x01-y04", "d02-x01-y05"});
}

// Analysis
void analyze(const Event& event) {

  const FastJets& fJets = apply<FastJets>(event, "Jets");

  // Fill the jet pT spectra
  const Jets& jets = fJets.jetsByPt(Cuts::pt > 100. * GeV && Cuts::absrap < 2.5);
  for (const Jet& j : jets) {
    _h_sigma->fill(fabs(j.rapidity()), j.pT() / GeV);
  }

  // Require two jets
  const Jets& dijets = fJets.jetsByPt(Cuts::pt > 30. * GeV && Cuts::absrap < 2.5);
  if (dijets.size() > 1) {
    if (dijets[0].momentum().pT() / GeV > 60.) {
      // Fill the invariant mass histogram
      double ymax = max(dijets[0].momentum().absrapidity(), dijets[1].momentum().absrapidity());
      double invMass = FourMomentum(dijets[0].momentum() + dijets[1].momentum()).mass();
      _h_invMass->fill(fabs(ymax), invMass);
    }
  }
}


// Scale histograms by the production cross section
void finalize() {
  scale(_h_sigma, crossSection() / picobarn / sumOfWeights() / 2.0);
  scale(_h_invMass, crossSection() / picobarn / sumOfWeights() / 2.0);
  divByGroupWidth({_h_sigma, _h_invMass});
}

private:

Histo1DGroupPtr _h_sigma;
Histo1DGroupPtr _h_invMass;

};

RIVET_DECLARE_PLUGIN(CMS_2013_I1208923); } ```