Rivet analyses

title: MC_WWJETS

Monte Carlo validation observables for $W^+[e^+ \, \nu]W^-[\mu^- \, \nu]$ + jets production

Experiment: ()

Status: VALIDATED

Authors: - Frank Siegert

References: none listed

Beams: * *

Beam energies: ANY

Run details: - $WW$ + jets analysis.

In addition to the typical jet observables this analysis contains observables related to properties of the WW-pair momentum, correlations between the WW, properties of the W bosons, properties of the leptons, correlations between the opposite charge leptons and correlations with jets.

Source code:MC_WWJETS.cc

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

include "Rivet/Analyses/MC_JETS_BASE.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

/// @brief MC validation analysis for e+mu W^+W^- + jets events class MC_WWJETS : public MC_JETS_BASE { public:

/// Default constructor
MC_WWJETS()
    : MC_JETS_BASE("MC_WWJETS", 4, "Jets") { }


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

/// Book histograms
void init() {

  declare("MET", MissingMomentum());

  // Find electrons with cuts from input options
  const double ETAECUT = getOption<double>("ABSETAEMAX", 3.5);
  const double PTECUT = getOption<double>("PTEMIN", 25.);
  const Cut cut_e = Cuts::abseta < ETAECUT && Cuts::pT > PTECUT * GeV;
  LeptonFinder ef(0.2, cut_e && Cuts::abspid == PID::ELECTRON);
  declare(ef, "Elecs");

  // Find muons with cuts from input options
  const double ETAMUCUT = getOption<double>("ABSETAMUMAX", 3.5);
  const double PTMUCUT = getOption<double>("PTMUMIN", 25.);
  const Cut cut_m = Cuts::abseta < ETAMUCUT && Cuts::pT > PTMUCUT * GeV;
  LeptonFinder mf(0.2, cut_m && Cuts::abspid == PID::MUON);
  declare(mf, "Muons");

  // Set pT cut, jet alg, and clustering radius from input options
  const double jetptcut = getOption<double>("PTJMIN", 20.0);
  _jetptcut = jetptcut * GeV;
  const double R = getOption<double>("R", 0.4);
  JetAlg clusterAlgo;
  const string algoopt = getOption("ALGO", "ANTIKT");
  if (algoopt == "KT") {
    clusterAlgo = JetAlg::KT;
  }
  else if (algoopt == "CA") {
    clusterAlgo = JetAlg::CA;
  }
  else if (algoopt == "ANTIKT") {
    clusterAlgo = JetAlg::ANTIKT;
  }
  else {
    MSG_WARNING("Unknown jet clustering algorithm option " + algoopt + ". Defaulting to anti-kT");
    clusterAlgo = JetAlg::ANTIKT;
  }

  // Find jets with clustering radius from input option
  VetoedFinalState jetinput;
  jetinput.addVetoOnThisFinalState(ef).addVetoOnThisFinalState(mf);
  FastJets fj(jetinput, clusterAlgo, R);
  declare(fj, "Jets");


  // Histogram correlations with jets and global quantities
  book(_h_WW_jet1_deta, "WW_jet1_deta", 70, -7.0, 7.0);
  book(_h_WW_jet1_dR, "WW_jet1_dR", 25, 1.5, 7.0);
  book(_h_We_jet1_dR, "We_jet1_dR", 25, 0.0, 7.0);
  //
  book(_h_HT, "HT", logspace(100, 100.0, 0.5 * (sqrtS() > 0. ? sqrtS() : 14000.)));
  book(_h_jets_m_12, "jets_m_12", logspace(100, 1.0, 0.25 * (sqrtS() > 0. ? sqrtS() : 14000.)));

  MC_JETS_BASE::init();
}


/// Do the analysis
void analyze(const Event& event) {

  // MET cut
  const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
  if (pmiss.pT() < 25 * GeV) vetoEvent;

  // Identify the closest-matching l+MET to m == mW
  /// @note Dubious strategy, given there are two neutrinos...
  const Particles& es = apply<LeptonFinder>(event, "Elecs").particles();
  const int iefound = closestMatchIndex(es, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);
  const Particles& mus = apply<LeptonFinder>(event, "Muons").particles();
  const int imfound = closestMatchIndex(mus, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);

  // Require two valid W candidates
  if (iefound < 0 || imfound < 0) vetoEvent;

  // Get momenta
  FourMomentum pe = es[iefound].mom();
  FourMomentum pm = mus[imfound].mom();
  FourMomentum pww = pe + pm + pmiss;

  // Get jets and compute obs relative to the WW objects
  const Jets& jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > _jetptcut);
  if (jets.size() > 0) {
    _h_WW_jet1_deta->fill(pww.eta() - jets[0].eta());
    _h_WW_jet1_dR->fill(deltaR(pww, jets[0].momentum()));
    _h_We_jet1_dR->fill(deltaR(pe, jets[0].momentum()));
  }
  const double HT = sum(jets, Kin::pT, pe.pT() + pm.pT() + pmiss.pT());
  if (HT > 0.0) _h_HT->fill(HT / GeV);

  if (jets.size() > 1) {
    const FourMomentum jet1 = jets[0].momentum();
    const FourMomentum jet2 = jets[1].momentum();
    _h_jets_m_12->fill((jet1 + jet2).mass() / GeV);
  }

  MC_JETS_BASE::analyze(event);
}


/// Finalize
void finalize() {
  const double norm = crossSection() / picobarn / sumOfWeights();
  scale(_h_WW_jet1_deta, norm);
  scale(_h_WW_jet1_dR, norm);
  scale(_h_We_jet1_dR, norm);
  scale(_h_jets_m_12, norm);
  scale(_h_HT, norm);
  MC_JETS_BASE::finalize();
}

/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr _h_WW_jet1_deta;
Histo1DPtr _h_WW_jet1_dR;
Histo1DPtr _h_We_jet1_dR;
Histo1DPtr _h_jets_m_12;
Histo1DPtr _h_HT;
/// @}

};

RIVET_DECLARE_PLUGIN(MC_WWJETS);

} ```