Rivet analyses

title: ATLAS_2012_I1083318

$W$+jets production at 7 TeV

Experiment: ATLAS (LHC)

Inspire ID: 1083318

Status: VALIDATED

Authors: - Frank Siegert

References: - Expt page: ATLAS-STDM-2011-08 - arXiv: 1201.1276

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - W+jet events in either the electron or the muon decay channel (but not both).

Differential cross-sections of properties of the four leading jets in $W$+jets production, using the full 2010 dataset of 36 pb$^-1$. Observables include jet multiplicities, $pT$, $H_T$, angular distances, and others. All observables are available using jets with $pT>30$ and $pT>20$ GeV.

Source code:ATLAS_2012_I1083318.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/IdentifiedFinalState.hh"

include "Rivet/Projections/LeadingParticlesFinalState.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

/// ATLAS W + jets production at 7 TeV class ATLAS_2012_I1083318 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2012_I1083318);


/// @name Analysis methods
/// @{

/// Book histograms and initialise projections before the run
void init() {

  FinalState fs;
  Cut cuts = Cuts::abseta < 2.5 && Cuts::pT > 20 * GeV;
  LeptonFinder leptons(0.1, cuts && (Cuts::abspid == PID::ELECTRON || Cuts::abspid == PID::MUON));
  declare(leptons, "leptons");

  // Leading neutrinos for Etmiss
  LeadingParticlesFinalState neutrinos(fs);
  neutrinos.addParticleIdPair(PID::NU_E);
  neutrinos.addParticleIdPair(PID::NU_MU);
  neutrinos.setLeadingOnly(true);
  declare(neutrinos, "neutrinos");

  // Input for the jets: "Neutrinos, electrons, and muons from decays of the
  // massive W boson were not used"
  VetoedFinalState veto;
  veto.addVetoOnThisFinalState(leptons);
  veto.addVetoOnThisFinalState(neutrinos);
  FastJets jets(veto, JetAlg::ANTIKT, 0.4, JetMuons::ALL, JetInvisibles::DECAY);
  declare(jets, "jets");

  for (size_t i = 0; i < 2; ++i) {
    book(_h_NjetIncl[i], 1, 1, i + 1);
    book(_h_RatioNjetIncl[i], 2, 1, i + 1);
    book(_h_FirstJetPt_1jet[i], 3, 1, i + 1);
    book(_h_FirstJetPt_2jet[i], 4, 1, i + 1);
    book(_h_FirstJetPt_3jet[i], 5, 1, i + 1);
    book(_h_FirstJetPt_4jet[i], 6, 1, i + 1);
    book(_h_SecondJetPt_2jet[i], 7, 1, i + 1);
    book(_h_SecondJetPt_3jet[i], 8, 1, i + 1);
    book(_h_SecondJetPt_4jet[i], 9, 1, i + 1);
    book(_h_ThirdJetPt_3jet[i], 10, 1, i + 1);
    book(_h_ThirdJetPt_4jet[i], 11, 1, i + 1);
    book(_h_FourthJetPt_4jet[i], 12, 1, i + 1);
    book(_h_Ht_1jet[i], 13, 1, i + 1);
    book(_h_Ht_2jet[i], 14, 1, i + 1);
    book(_h_Ht_3jet[i], 15, 1, i + 1);
    book(_h_Ht_4jet[i], 16, 1, i + 1);
    book(_h_Minv_2jet[i], 17, 1, i + 1);
    book(_h_Minv_3jet[i], 18, 1, i + 1);
    book(_h_Minv_4jet[i], 19, 1, i + 1);
    book(_h_JetRapidity[i], 20, 1, i + 1);
    book(_h_DeltaYElecJet[i], 21, 1, i + 1);
    book(_h_SumYElecJet[i], 22, 1, i + 1);
    book(_h_DeltaR_2jet[i], 23, 1, i + 1);
    book(_h_DeltaY_2jet[i], 24, 1, i + 1);
    book(_h_DeltaPhi_2jet[i], 25, 1, i + 1);
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const DressedLeptons& leptons = apply<LeptonFinder>(event, "leptons").dressedLeptons();
  Particles neutrinos = apply<FinalState>(event, "neutrinos").particlesByPt();

  if (leptons.size() != 1 || (neutrinos.size() == 0)) vetoEvent;

  FourMomentum lepton = leptons[0].momentum();
  FourMomentum p_miss = neutrinos[0].momentum();
  if (p_miss.Et() < 25.0 * GeV) vetoEvent;

  double mT = sqrt(2.0 * lepton.pT() * p_miss.Et() * (1.0 - cos(lepton.phi() - p_miss.phi())));
  if (mT < 40.0 * GeV) vetoEvent;

  double jetcuts[] = {30.0 * GeV, 20.0 * GeV};
  for (size_t i = 0; i < 2; ++i) {
    Jets jets = apply<FastJets>(event, "jets").jetsByPt(Cuts::absrap < 4.4 && Cuts::pT > jetcuts[i]);
    idiscard(jets, deltaRLess(lepton, 0.5));

    const double HT = sum(jets, Kin::pT, lepton.pT() + p_miss.pT());

    _h_NjetIncl[i]->fill(0.0);

    // Njet>=1 observables
    if (jets.size() < 1) continue;
    _h_NjetIncl[i]->fill(1.0);
    _h_FirstJetPt_1jet[i]->fill(jets[0].pT());
    _h_JetRapidity[i]->fill(jets[0].rapidity());
    _h_Ht_1jet[i]->fill(HT);
    _h_DeltaYElecJet[i]->fill(lepton.rapidity() - jets[0].rapidity());
    _h_SumYElecJet[i]->fill(lepton.rapidity() + jets[0].rapidity());

    // Njet>=2 observables
    if (jets.size() < 2) continue;
    _h_NjetIncl[i]->fill(2.0);
    _h_FirstJetPt_2jet[i]->fill(jets[0].pT());
    _h_SecondJetPt_2jet[i]->fill(jets[1].pT());
    _h_Ht_2jet[i]->fill(HT);
    double m2_2jet = (jets[0].mom() + jets[1].mom()).mass2();
    _h_Minv_2jet[i]->fill(m2_2jet > 0.0 ? sqrt(m2_2jet) : 0.0);
    _h_DeltaR_2jet[i]->fill(deltaR(jets[0], jets[1]));
    _h_DeltaY_2jet[i]->fill(jets[0].rapidity() - jets[1].rapidity());
    _h_DeltaPhi_2jet[i]->fill(deltaPhi(jets[0], jets[1]));

    // Njet>=3 observables
    if (jets.size() < 3) continue;
    _h_NjetIncl[i]->fill(3.0);
    _h_FirstJetPt_3jet[i]->fill(jets[0].pT());
    _h_SecondJetPt_3jet[i]->fill(jets[1].pT());
    _h_ThirdJetPt_3jet[i]->fill(jets[2].pT());
    _h_Ht_3jet[i]->fill(HT);
    double m2_3jet = (jets[0].mom() + jets[1].mom() + jets[2].mom()).mass2();
    _h_Minv_3jet[i]->fill(m2_3jet > 0.0 ? sqrt(m2_3jet) : 0.0);

    // Njet>=4 observables
    if (jets.size() < 4) continue;
    _h_NjetIncl[i]->fill(4.0);
    _h_FirstJetPt_4jet[i]->fill(jets[0].pT());
    _h_SecondJetPt_4jet[i]->fill(jets[1].pT());
    _h_ThirdJetPt_4jet[i]->fill(jets[2].pT());
    _h_FourthJetPt_4jet[i]->fill(jets[3].pT());
    _h_Ht_4jet[i]->fill(HT);
    double m2_4jet = (jets[0].mom() + jets[1].mom() + jets[2].mom() + jets[3].mom()).mass2();
    _h_Minv_4jet[i]->fill(m2_4jet > 0.0 ? sqrt(m2_4jet) : 0.0);

    // Njet>=5 observables
    if (jets.size() < 5) continue;
    _h_NjetIncl[i]->fill(5.0);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (size_t i = 0; i < 2; ++i) {

    // Construct jet multiplicity ratio
    for (size_t n = 1; n < _h_NjetIncl[i]->numBins(); ++n) {
      const auto& b0 = _h_NjetIncl[i]->bin(n);
      const auto& b1 = _h_NjetIncl[i]->bin(n + 1);
      double val = 0.0, err = 0.0;
      if (b0.sumW() && b1.sumW()) {
        val = b1.sumW() / b0.sumW();
        err = b1.sumW() / b0.sumW() * (b0.relErrW() + b1.relErrW());
      }
      _h_RatioNjetIncl[i]->bin(n).set(val, err);
    }

    // Scale all histos to the cross section
    const double factor = crossSection() / picobarn / sumOfWeights();
    scale(_h_DeltaPhi_2jet[i], factor);
    scale(_h_DeltaR_2jet[i], factor);
    scale(_h_DeltaY_2jet[i], factor);
    scale(_h_DeltaYElecJet[i], factor);
    scale(_h_FirstJetPt_1jet[i], factor);
    scale(_h_FirstJetPt_2jet[i], factor);
    scale(_h_FirstJetPt_3jet[i], factor);
    scale(_h_FirstJetPt_4jet[i], factor);
    scale(_h_FourthJetPt_4jet[i], factor);
    scale(_h_Ht_1jet[i], factor);
    scale(_h_Ht_2jet[i], factor);
    scale(_h_Ht_3jet[i], factor);
    scale(_h_Ht_4jet[i], factor);
    scale(_h_JetRapidity[i], factor);
    scale(_h_Minv_2jet[i], factor);
    scale(_h_Minv_3jet[i], factor);
    scale(_h_Minv_4jet[i], factor);
    scale(_h_NjetIncl[i], factor);
    scale(_h_SecondJetPt_2jet[i], factor);
    scale(_h_SecondJetPt_3jet[i], factor);
    scale(_h_SecondJetPt_4jet[i], factor);
    scale(_h_SumYElecJet[i], factor);
    scale(_h_ThirdJetPt_3jet[i], factor);
    scale(_h_ThirdJetPt_4jet[i], factor);
  }
}

/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr _h_DeltaPhi_2jet[2];
Histo1DPtr _h_DeltaR_2jet[2];
Histo1DPtr _h_DeltaY_2jet[2];
Histo1DPtr _h_DeltaYElecJet[2];
Histo1DPtr _h_FirstJetPt_1jet[2];
Histo1DPtr _h_FirstJetPt_2jet[2];
Histo1DPtr _h_FirstJetPt_3jet[2];
Histo1DPtr _h_FirstJetPt_4jet[2];
Histo1DPtr _h_FourthJetPt_4jet[2];
Histo1DPtr _h_Ht_1jet[2];
Histo1DPtr _h_Ht_2jet[2];
Histo1DPtr _h_Ht_3jet[2];
Histo1DPtr _h_Ht_4jet[2];
Histo1DPtr _h_JetRapidity[2];
Histo1DPtr _h_Minv_2jet[2];
Histo1DPtr _h_Minv_3jet[2];
Histo1DPtr _h_Minv_4jet[2];
Histo1DPtr _h_NjetIncl[2];
Estimate1DPtr _h_RatioNjetIncl[2];
Histo1DPtr _h_SecondJetPt_2jet[2];
Histo1DPtr _h_SecondJetPt_3jet[2];
Histo1DPtr _h_SecondJetPt_4jet[2];
Histo1DPtr _h_SumYElecJet[2];
Histo1DPtr _h_ThirdJetPt_3jet[2];
Histo1DPtr _h_ThirdJetPt_4jet[2];
/// @}

};

RIVET_DECLARE_PLUGIN(ATLAS_2012_I1083318);

} ```