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CMS_2011_S8968497

Dijet angular distributions and search for quark compositeness in $pp$ collisions at $\sqrt{s} = 7$ TeV
Experiment: CMS (LHC)
Inspire ID: 889175
Status: VALIDATED
Authors:
  • A. Hinzmann
References: Beams: p+ p+
Beam energies: (3500.0, 3500.0) GeV
Run details:
  • QCD dijet events

Measurement of dijet angular distributions in proton-proton collisions at a center-of-mass energy of 7 TeV. The data sample, collected with single jet triggers, has a total integrated luminosity of 36 pb$^{-1}$, with jets being reconstructed using the anti-$k_t$ clustering algorithm with $R=0.5$. The data are presented for the variable $\chi$ defined as $\chi = \exp(|y_1 - y_2|)$ where $y_1$ and $y_2$ are the rapidities of the two leading (highest $p_\perp$) jets.'

Source code: CMS_2011_S8968497.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FastJets.hh"
 4#include "Rivet/Tools/BinnedHistogram.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// Dijet angular distributions and search for quark compositeness at 7 TeV
10  class CMS_2011_S8968497 : public Analysis {
11  public:
12
13    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_S8968497);
14
15
16    void init() {
17      FinalState fs;
18      FastJets antikt(fs, FastJets::ANTIKT, 0.5);
19      declare(antikt, "ANTIKT");
20      {Histo1DPtr tmp; _h_chi_dijet.add(2200., 7000., book(tmp, 1, 1, 1));}
21      {Histo1DPtr tmp; _h_chi_dijet.add(1800., 2200., book(tmp, 2, 1, 1));}
22      {Histo1DPtr tmp; _h_chi_dijet.add(1400., 1800., book(tmp, 3, 1, 1));}
23      {Histo1DPtr tmp; _h_chi_dijet.add(1100., 1400., book(tmp, 4, 1, 1));}
24      {Histo1DPtr tmp; _h_chi_dijet.add( 850., 1100., book(tmp, 5, 1, 1));}
25      {Histo1DPtr tmp; _h_chi_dijet.add( 650.,  850., book(tmp, 6, 1, 1));}
26      {Histo1DPtr tmp; _h_chi_dijet.add( 500.,  650., book(tmp, 7, 1, 1));}
27      {Histo1DPtr tmp; _h_chi_dijet.add( 350.,  500., book(tmp, 8, 1, 1));}
28      {Histo1DPtr tmp; _h_chi_dijet.add( 250.,  350., book(tmp, 9, 1, 1));}
29    }
30
31
32    void analyze(const Event& event) {
33      const double weight = 1.0;
34      const Jets& jets = apply<JetAlg>(event, "ANTIKT").jetsByPt();
35      if (jets.size() < 2) vetoEvent;
36      FourMomentum j0(jets[0].momentum());
37      FourMomentum j1(jets[1].momentum());
38      double y0 = j0.rapidity();
39      double y1 = j1.rapidity();
40      if (fabs(y0+y1)/2. > 1.11) vetoEvent;
41      double mjj = FourMomentum(j0+j1).mass();
42      double chi = exp(fabs(y0-y1));
43      if(chi<16.)  _h_chi_dijet.fill(mjj, chi, weight);
44    }
45
46
47    void finalize() {
48      for (Histo1DPtr hist : _h_chi_dijet.histos()) {
49        normalize(hist);
50      }
51    }
52
53
54  private:
55
56    BinnedHistogram _h_chi_dijet;
57
58  };
59
60
61
62  RIVET_DECLARE_ALIASED_PLUGIN(CMS_2011_S8968497, CMS_2011_I889175);
63
64}