Rivet analyses

title: CMS_2016_I1473674

Measurement of the differential cross sections for top quark pair production as a function of kinematic event variables at sqrt(s) = 8 TeV

Experiment: CMS (LHC)

Inspire ID: 1473674

Status: VALIDATED

Authors: - Markus Seidel - Lukas Kreczko - Emyr Clement

References: - arXiv: 1607.00837

Beams: p+ p+

Beam energies: (4000.0, 4000.0)GeV

Run details: - ttbar events at sqrt(s) = 8 TeV (inclusive or lepton+jets decay mode) Top quarks are expected in the event record to identify the decay mode.

Measurements are reported of the normalized differential cross sections for top quark pair production with respect to four kinematic event variables: the missing transverse energy; the scalar sum of the jet transverse momentum (pT); the scalar sum of the pT of all objects in the event; and the pT of leptonically decaying W bosons from top quark decays.

Source code:CMS_2016_I1473674.cc

```c++

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/IdentifiedFinalState.hh"

include "Rivet/Projections/InvMassFinalState.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/PartonicTops.hh"

include "Rivet/Projections/PromptFinalState.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

class CMS_2016_I1473674 : public Analysis { public:

// Minimal constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2016_I1473674);


// Set up projections and book histograms
void init() {

  // Complete final state
  FinalState fs;

  // Parton level top quarks
  declare(PartonicTops(TopDecay::E_MU, PromptEMuFromTau::NO), "LeptonicPartonTops");
  declare(PartonicTops(TopDecay::HADRONIC), "HadronicPartonTops");

  // Projections for dressed electrons and muons
  IdentifiedFinalState photons(fs);
  photons.acceptIdPair(PID::PHOTON);
  //
  IdentifiedFinalState el_id(fs);
  el_id.acceptIdPair(PID::ELECTRON);
  PromptFinalState electrons(el_id);
  declare(electrons, "Electrons");
  LeptonFinder dressed_electrons(electrons, photons, 0.1);
  declare(dressed_electrons, "DressedElectrons");
  //
  IdentifiedFinalState mu_id(fs);
  mu_id.acceptIdPair(PID::MUON);
  PromptFinalState muons(mu_id);
  declare(muons, "Muons");
  LeptonFinder dressed_muons(muons, photons, 0.1);
  declare(dressed_muons, "DressedMuons");

  // Projection for jets
  VetoedFinalState fs_jets;
  fs_jets.addVetoOnThisFinalState(dressed_muons);
  declare(FastJets(fs_jets, JetAlg::ANTIKT, 0.5), "Jets");

  // Projections for MET
  declare(MissingMomentum(), "MET");


  // Booking of histograms
  book(_hist_met, 5, 1, 1);
  book(_hist_ht, 6, 1, 1);
  book(_hist_st, 7, 1, 1);
  book(_hist_wpt, 8, 1, 1);
}


/// Per-event analysis
void analyze(const Event& event) {

  // Select ttbar -> lepton+jets at parton level, removing tau decays
  const Particles leptonicpartontops = apply<ParticleFinder>(event, "LeptonicPartonTops").particlesByPt();
  if (leptonicpartontops.size() != 1) vetoEvent;
  const Particles hadronicpartontops = apply<ParticleFinder>(event, "HadronicPartonTops").particlesByPt();
  if (hadronicpartontops.size() != 1) vetoEvent;

  // Select ttbar -> lepton+jets at particle level
  const LeptonFinder& dressed_electrons = apply<LeptonFinder>(event, "DressedElectrons");
  const LeptonFinder& dressed_muons = apply<LeptonFinder>(event, "DressedMuons");
  if (dressed_electrons.dressedLeptons().size() + dressed_muons.dressedLeptons().size() != 1) vetoEvent;
  const FourMomentum lepton = (dressed_electrons.dressedLeptons().empty() ? dressed_muons
                                                                          : dressed_electrons)
                                  .dressedLeptons()[0];

  // MET
  const MissingMomentum& met = apply<MissingMomentum>(event, "MET");
  _hist_met->fill(met.visibleMomentum().pT() / GeV);

  // HT and ST
  const FastJets& jetpro = apply<FastJets>(event, "Jets");
  const Jets jets = jetpro.jetsByPt(Cuts::pT > 20 * GeV);

  double ht = 0.0;
  for (const Jet& j : jets) {
    if (deltaR(j.momentum(), lepton) > 0.3) {
      ht += j.pT();
    }
  }

  double st = ht + lepton.pT() + met.visibleMomentum().pT();
  _hist_ht->fill(ht / GeV);
  _hist_st->fill(st / GeV);

  // WPT
  const FourMomentum w = lepton - met.visibleMomentum();
  _hist_wpt->fill(w.pT() / GeV);
}


/// Normalize histograms
void finalize() {
  normalize(_hist_met);
  normalize(_hist_ht);
  normalize(_hist_st);
  normalize(_hist_wpt);
}

private:

Histo1DPtr _hist_met, _hist_ht, _hist_st, _hist_wpt;

};

RIVET_DECLARE_PLUGIN(CMS_2016_I1473674);

} ```