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CMS_2011_I889175

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_I889175.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FastJets.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// Dijet angular distributions and search for quark compositeness at 7 TeV
 9  class CMS_2011_I889175 : public Analysis {
10  public:
11
12    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I889175);
13
14
15    void init() {
16
17      FinalState fs;
18      FastJets antikt(fs, JetAlg::ANTIKT, 0.5);
19      declare(antikt, "ANTIKT");
20
21      book(_h_chi_dijet, {250., 350., 500., 650., 850., 1100., 1400., 1800., 2200., 7000.});
22      for (auto& b : _h_chi_dijet->bins()) {
23        book(b, _h_chi_dijet->numBins() - b.index() + 1, 1, 1);
24      }
25    }
26
27
28    void analyze(const Event& event) {
29      const Jets& jets = apply<JetFinder>(event, "ANTIKT").jetsByPt();
30      if (jets.size() < 2) vetoEvent;
31      FourMomentum j0(jets[0].momentum());
32      FourMomentum j1(jets[1].momentum());
33      double y0 = j0.rapidity();
34      double y1 = j1.rapidity();
35      if (fabs(y0+y1)/2. > 1.11) vetoEvent;
36      double mjj = FourMomentum(j0+j1).mass();
37      double chi = exp(fabs(y0-y1));
38      if(chi<16.)  _h_chi_dijet->fill(mjj, chi);
39    }
40
41
42    void finalize() {
43      normalize(_h_chi_dijet);
44    }
45
46
47  private:
48
49    Histo1DGroupPtr _h_chi_dijet;
50
51  };
52
53
54
55  RIVET_DECLARE_ALIASED_PLUGIN(CMS_2011_I889175, CMS_2011_S8968497);
56
57}