Rivet analyses

title: CMS_2015_I1370682_PARTON

Parton-level differential top-quark pair production cross-sections in $pp$ collisions at $\sqrt{s} = 8\,\TeV$

Experiment: CMS (LHC)

Inspire ID: 1370682

Status: VALIDATED

Authors: - Jungwan John Goh - Markus Seidel

References: - Eur.Phys.J. C75 (2015) 542

Beams: p+ p+

Beam energies: (4000.0, 4000.0)GeV

Run details: - $t\bar{t}$ events at $\sqrt{s}= 8\,\TeV$. Top quarks with physical momenta must be present in the event record.

The normalized parton level differential cross section for top quark pair production is measured in $pp$ collisions at a centre-of-mass energy of 8\,\TeV.

Source code:CMS_2015_I1370682_PARTON.cc

```c++

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/PartonicTops.hh"

namespace Rivet {

class CMS_2015_I1370682_PARTON : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2015_I1370682_PARTON);


/// Book projections and histograms
void init() {
  declare(PartonicTops(TopDecay::E_MU, PromptEMuFromTau::NO), "LeptonicPartonTops");
  declare(PartonicTops(TopDecay::HADRONIC), "HadronicPartonTops");

  book(_hSL_topPt, 15, 1, 1);
  book(_hSL_topPtTtbarSys, 16, 1, 1);
  book(_hSL_topY, 17, 1, 1);
  book(_hSL_ttbarDelPhi, 18, 1, 1);
  book(_hSL_topPtLead, 19, 1, 1);
  book(_hSL_topPtSubLead, 20, 1, 1);
  book(_hSL_ttbarPt, 21, 1, 1);
  book(_hSL_ttbarY, 22, 1, 1);
  book(_hSL_ttbarMass, 23, 1, 1);

  book(_hDL_topPt, 24, 1, 1);
  book(_hDL_topPtTtbarSys, 25, 1, 1);
  book(_hDL_topY, 26, 1, 1);
  book(_hDL_ttbarDelPhi, 27, 1, 1);
  book(_hDL_topPtLead, 28, 1, 1);
  book(_hDL_topPtSubLead, 29, 1, 1);
  book(_hDL_ttbarPt, 30, 1, 1);
  book(_hDL_ttbarY, 31, 1, 1);
  book(_hDL_ttbarMass, 32, 1, 1);
}


void analyze(const Event& event) {

  // Do the analysis only for the ttbar full leptonic or semileptonic channel, without tau decay
  const Particles leptonicpartontops = apply<ParticleFinder>(event, "LeptonicPartonTops").particlesByPt();
  const Particles hadronicpartontops = apply<ParticleFinder>(event, "HadronicPartonTops").particlesByPt();
  const bool isSemilepton = (leptonicpartontops.size() == 1 && hadronicpartontops.size() == 1);
  const bool isDilepton = (leptonicpartontops.size() == 2 && hadronicpartontops.size() == 0);
  if (!isSemilepton && !isDilepton) vetoEvent;

  // Parton level at full phase space
  // Fill top quarks defined in the parton level, full phase space
  const FourMomentum t1P4 = leptonicpartontops[0];
  const FourMomentum t2P4 = isSemilepton ? hadronicpartontops[0] : leptonicpartontops[1];
  const double t1Pt = t1P4.pT(), t2Pt = t2P4.pT();
  const FourMomentum ttbarP4 = t1P4 + t2P4;
  const FourMomentum t1P4AtCM = LorentzTransform::mkFrameTransformFromBeta(ttbarP4.betaVec())
                                    .transform(t1P4);
  const double dPhi = deltaPhi(t1P4.phi(), t2P4.phi());

  if (isSemilepton) {
    _hSL_topPt->fill(t1Pt);
    _hSL_topPt->fill(t2Pt);
    _hSL_topPtTtbarSys->fill(t1P4AtCM.pT());
    _hSL_topY->fill(t1P4.rapidity());
    _hSL_topY->fill(t2P4.rapidity());
    _hSL_ttbarDelPhi->fill(dPhi);
    _hSL_topPtLead->fill(std::max(t1Pt, t2Pt));
    _hSL_topPtSubLead->fill(std::min(t1Pt, t2Pt));
    _hSL_ttbarPt->fill(ttbarP4.pT());
    _hSL_ttbarY->fill(ttbarP4.rapidity());
    _hSL_ttbarMass->fill(ttbarP4.mass());
  }
  else { // if (isDilepton) {
    _hDL_topPt->fill(t1Pt);
    _hDL_topPt->fill(t2Pt);
    _hDL_topPtTtbarSys->fill(t1P4AtCM.pT());
    _hDL_topY->fill(t1P4.rapidity());
    _hDL_topY->fill(t2P4.rapidity());
    _hDL_ttbarDelPhi->fill(dPhi);
    _hDL_topPtLead->fill(std::max(t1Pt, t2Pt));
    _hDL_topPtSubLead->fill(std::min(t1Pt, t2Pt));
    _hDL_ttbarPt->fill(ttbarP4.pT());
    _hDL_ttbarY->fill(ttbarP4.rapidity());
    _hDL_ttbarMass->fill(ttbarP4.mass());
  }
}


void finalize() {
  normalize(_hSL_topPt);
  normalize(_hSL_topPtTtbarSys);
  normalize(_hSL_topY);
  normalize(_hSL_ttbarDelPhi);
  normalize(_hSL_topPtLead);
  normalize(_hSL_topPtSubLead);
  normalize(_hSL_ttbarPt);
  normalize(_hSL_ttbarY);
  normalize(_hSL_ttbarMass);
  normalize(_hDL_topPt);
  normalize(_hDL_topPtTtbarSys);
  normalize(_hDL_topY);
  normalize(_hDL_ttbarDelPhi);
  normalize(_hDL_topPtLead);
  normalize(_hDL_topPtSubLead);
  normalize(_hDL_ttbarPt);
  normalize(_hDL_ttbarY);
  normalize(_hDL_ttbarMass);
}

private:

/// @name Histograms
/// @{
Histo1DPtr _hSL_topPt, _hSL_topPtTtbarSys, _hSL_topY, _hSL_ttbarDelPhi, _hSL_topPtLead, _hSL_topPtSubLead,
    _hSL_ttbarPt, _hSL_ttbarY, _hSL_ttbarMass;
Histo1DPtr _hDL_topPt, _hDL_topPtTtbarSys, _hDL_topY, _hDL_ttbarDelPhi, _hDL_topPtLead, _hDL_topPtSubLead,
    _hDL_ttbarPt, _hDL_ttbarY, _hDL_ttbarMass;
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2015_I1370682_PARTON);

} ```