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## Rivet analyses reference

### CMS_2011_S9088458

Measurement of ratio of the 3-jet over 2-jet cross section in $pp$ collisions at $\sqrt{s} = 7$ TeV
Experiment: CMS (LHC)
Inspire ID: 912560
Status: VALIDATED
Authors:
• Tomo Umer
References:
• Phys. Lett. B 702 (2011) 336
Beams: p+ p+
Beam energies: (3500.0, 3500.0) GeV
Run details:
• Inclusive QCD at 7 TeV. $\hat{p_\perp}$ (or equivalent) greater than 30 GeV

A measurement of the ratio of the inclusive 3-jet to 2-jet cross sections as a function of the total jet transverse momentum, $H_T$, in the range $0.2 < H_T < 2.5$ TeV is presented. The data have been collected at a proton--proton centre-of-mass energy of 7\;TeV with the CMS detector at the LHC, and correspond to an integrated luminosity of 36/pb. Jets are anti-$k_t$ with $R = 0.5$, $p_\perp > 50\;\text{GeV}$ and $|\eta| < 2.5$.

Source code: CMS_2011_S9088458.cc
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Tools/BinnedHistogram.hh" #include "Rivet/Projections/FinalState.hh" #include "Rivet/Projections/FastJets.hh" namespace Rivet { /// CMS ratio of 3-jet to 2-jet cross-sections class CMS_2011_S9088458 : public Analysis { public: CMS_2011_S9088458() : Analysis("CMS_2011_S9088458") { } void init() { FinalState fs; FastJets akt(fs, FastJets::ANTIKT, 0.5); declare(akt, "antikT"); _h_tmp_dijet = Histo1D(refData(1, 1, 1)); _h_tmp_trijet = Histo1D(refData(1, 1, 1)); _h_r32 = bookScatter2D(1, 1, 1); } void analyze(const Event & event) { const double weight = event.weight(); Jets highpT_jets; double HT = 0; foreach(const Jet & jet, apply(event, "antikT").jetsByPt(50.0*GeV)) { if (jet.abseta() < 2.5) { highpT_jets.push_back(jet); HT += jet.pT(); } } if (highpT_jets.size() < 2) vetoEvent; if (highpT_jets.size() >= 2) _h_tmp_dijet.fill(HT/TeV, weight); if (highpT_jets.size() >= 3) _h_tmp_trijet.fill(HT/TeV, weight); } void finalize() { divide(_h_tmp_trijet, _h_tmp_dijet, _h_r32); } private: Histo1D _h_tmp_dijet, _h_tmp_trijet; Scatter2DPtr _h_r32; }; // A hook for the plugin system DECLARE_RIVET_PLUGIN(CMS_2011_S9088458); }