Rivet analyses

title: ATLAS_2014_I1325553

Measurement of the inclusive jet cross-section at 7 TeV

Experiment: ATLAS (LHC)

Inspire ID: 1325553

Status: VALIDATED

Authors: - Vojtech Pleskot

References: - Expt page: ATLAS-STDM-2013-11 - arXiv: 1410.8857

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - p p -> jet + X. $\sqrt{s} = 7$~TeV.

Measurement of the inclusive jet cross-section in proton--proton collisions at a centre-of-mass energy of 7 TeV using a data set corresponding to an integrated luminosity of 4.5/fb collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-$k_t$ algorithm with radius parameter values of 0.4 and 0.6. The double-differential cross-sections are presented as a function of the jet transverse momentum and the jet rapidity, covering jet transverse momenta from 100 GeV to 2 TeV.

Source code:ATLAS_2014_I1325553.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// Jet mass as a function of ystar class ATLAS_2014_I1325553 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2014_I1325553);

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

/// Book histograms and initialise projections before the run
void init() {

  const FinalState fs;
  declare(fs, "FinalState");

  FastJets fj04(fs, JetAlg::ANTIKT, 0.4);
  fj04.useInvisibles();
  declare(fj04, "AntiKT04");

  FastJets fj06(fs, JetAlg::ANTIKT, 0.6);
  fj06.useInvisibles();
  declare(fj06, "AntiKT06");

  const vector<double> ybins{0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0};

  size_t ptDsOffset = 0;
  for (size_t alg = 0; alg < 2; ++alg) {
    book(_pt[alg], ybins);
    for (auto& b : _pt[alg]->bins()) {
      book(b, 1 + ptDsOffset, 1, 1);
      ++ptDsOffset;
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  Jets jetAr[2];
  jetAr[AKT4] = apply<FastJets>(event, "AntiKT04").jetsByPt(Cuts::pT > 100 * GeV && Cuts::absrap < 3.0);
  jetAr[AKT6] = apply<FastJets>(event, "AntiKT06").jetsByPt(Cuts::pT > 100 * GeV && Cuts::absrap < 3.0);

  // Loop over jet "radii" used in analysis
  for (size_t alg = 0; alg < 2; ++alg) {

    // fill the 1D pt histograms with all the jets passing the cuts
    for (const Jet& jet : jetAr[alg]) {
      const double absrap = jet.absrap();
      if (absrap < 3.0) {
        const double pt = jet.pT();
        if (pt / GeV > 100 * GeV) {
          _pt[alg]->fill(absrap, pt / GeV);
        }
      }
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  /// Print summary info
  const double xs_norm_factor = 0.5 * crossSection() / picobarn / sumOfWeights();
  scale(_pt, xs_norm_factor);
  divByGroupWidth(_pt);
}

/// @}

private:

// Data members like post-cuts event weight counters go here
enum Alg { AKT4 = 0, AKT6 = 1 };

/// The inclusive jet spectrum binned in rapidity for akt6 and akt4 jets (array index is jet type from enum above)
Histo1DGroupPtr _pt[2];

};

RIVET_DECLARE_PLUGIN(ATLAS_2014_I1325553);

} ```