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CMS_2016_I1459051

Measurement of the inclusive jet cross-section in $pp$ collisions at $\sqrt{s} = 13 \text{TeV}$
Experiment: CMS (LHC)
Inspire ID: 1459051
Status: VALIDATED
Authors:
  • Paolo Gunnellini
References:
  • Eur.Phys.J. C76 (2016) no.8, 451
  • CERN-EP-2016-104
  • Public page: CMS-SMP-15-007
Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
  • Inclusive hard QCD at 13 TeV center-of-mass energy, and ptHat (or equivalent) greater than 90 GeV

A measurement of the double-differential inclusive jet cross section as a function of jet transverse momentum pT and absolute jet rapidity |y| is presented. The analysis is based on proton-proton collisions collected by the CMS experiment at the LHC at a centre-of-mass energy of 13 TeV. The data samples correspond to integrated luminosities of 71 and 44 pb-1 for |y| < 3 and 3.2 < |y| < 4.7, respectively. Jets are reconstructed with the anti-kt clustering algorithm for two jet sizes, R, of 0.7 and 0.4, in a phase space region covering jet pT up to 2 TeV and jet rapidity up to |y| = 4.7. Predictions of perturbative quantum chromodynamics at next-to-leading order precision, complemented with electroweak and nonperturbative corrections, are used to compute the absolute scale and the shape of the inclusive jet cross section. The cross-section difference in $R$, when going to a smaller jet size of 0.4, is best described by Monte Carlo event generators with next-to-leading order predictions matched to parton showering, hadronisation, and multiparton interactions. In the phase space accessible with the new data, this measurement provides a first indication that jet physics is as well understood at $\sqrt(s) = 13 \text{TeV}$ as at smaller centre-of-mass energies.

Source code: CMS_2016_I1459051.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/FastJets.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// Inclusive jet pT at 13 TeV
10  class CMS_2016_I1459051 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2016_I1459051);
15
16
17    /// Book histograms and initialize projections:
18    void init() {
19
20      // Initialize the projections
21      const FinalState fs;
22      declare(FastJets(fs, JetAlg::ANTIKT, 0.4), "JetsAK4");
23      declare(FastJets(fs, JetAlg::ANTIKT, 0.7), "JetsAK7");
24
25      // Book sets of histograms, binned in absolute rapidity
26      book(_hist_sigmaAK7, {0., 0.5, 1., 1.5, 2., 2.5, 3.});
27      book(_hist_sigmaAK4, {0., 0.5, 1., 1.5, 2., 2.5, 3.});
28      for (size_t i=1; i < _hist_sigmaAK7->numBins()+1; ++i) {
29        book(_hist_sigmaAK7->bin(i), i, 1, 1);
30        book(_hist_sigmaAK4->bin(i), 7+i, 1, 1);
31      }
32      book(_hist_sigmaAK7Forward, 7, 1, 1);
33      book(_hist_sigmaAK4Forward, 14, 1, 1);
34
35    }
36
37
38    /// Per-event analysis
39    void analyze(const Event &event) {
40
41      // AK4 jets
42      const FastJets& fjAK4 = apply<FastJets>(event, "JetsAK4");
43      const Jets& jetsAK4 = fjAK4.jets(Cuts::ptIn(114*GeV, 2200.0*GeV) && Cuts::absrap < 4.7);
44      for (const Jet& j : jetsAK4) {
45        _hist_sigmaAK4->fill(j.absrap(), j.pT());
46        if (inRange(j.absrap(), 3.2, 4.7)) _hist_sigmaAK4Forward->fill(j.pT());
47      }
48
49      // AK7 jets
50      const FastJets& fjAK7 = apply<FastJets>(event, "JetsAK7");
51      const Jets& jetsAK7 = fjAK7.jets(Cuts::ptIn(114*GeV, 2200.0*GeV) && Cuts::absrap < 4.7);
52      for (const Jet& j : jetsAK7) {
53        _hist_sigmaAK7->fill(j.absrap(), j.pT());
54        if (inRange(j.absrap(), 3.2, 4.7)) _hist_sigmaAK7Forward->fill(j.pT());
55      }
56
57    }
58
59
60    // Finalize
61    void finalize() {
62      /// @note Extra division factor is the *signed* dy, i.e. 2*d|y|
63      scale(_hist_sigmaAK4, crossSection()/picobarn/sumOfWeights()/2.0);
64      scale(_hist_sigmaAK7, crossSection()/picobarn/sumOfWeights()/2.0);
65      scale(_hist_sigmaAK4Forward,crossSection()/picobarn/sumOfWeights()/3.0);
66      scale(_hist_sigmaAK7Forward,crossSection()/picobarn/sumOfWeights()/3.0);
67      divByGroupWidth({_hist_sigmaAK4, _hist_sigmaAK7});
68    }
69
70
71    /// @name Histograms
72    /// @{
73    Histo1DGroupPtr _hist_sigmaAK4;
74    Histo1DGroupPtr _hist_sigmaAK7;
75    Histo1DPtr _hist_sigmaAK4Forward;
76    Histo1DPtr _hist_sigmaAK7Forward;
77    /// @}
78
79  };
80
81
82  RIVET_DECLARE_PLUGIN(CMS_2016_I1459051);
83
84}