Rivet analyses

title: MC_WJETS

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

Experiment: ()

Status: VALIDATED

Authors: - Frank Siegert - Christian Gutschow

References: none listed

Beams: * *

Beam energies: ANY

Run details: - $\ell \, \nu$ + jets analysis.

Monte Carlo validation observables for $W[\ell \, \nu]$ + jets production 60 GeV $<m_W<$ 100 GeV cut applied.

Source code:MC_WJETS.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/PromptFinalState.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

/// @brief MC validation analysis for W + jets events class MC_WJETS : public MC_JETS_BASE { public:

/// Default constructor
MC_WJETS(string name = "MC_WJETS")
    : MC_JETS_BASE(name, 4, "Jets") { }


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

/// Book histograms
void init() {

  // Use analysis options
  _dR = (getOption("SCHEME") == "BARE") ? 0.0 : 0.2;
  _lepton = (getOption("LMODE") == "MU") ? PID::MUON : PID::ELECTRON;
  const double ETACUT = getOption<double>("ABSETALMAX", 3.5);
  const double PTCUT = getOption<double>("PTLMIN", 25.);
  const Cut cut = Cuts::abseta < ETACUT && Cuts::pT > PTCUT * GeV;

  // Define projections
  declare("MET", MissingMomentum());
  LeptonFinder lf(_dR, cut && Cuts::abspid == _lepton);
  declare(lf, "Leptons");

  // Set pT cut, jet alg, and clustering radius from input options
  _jetptcut = getOption<double>("PTJMIN", 20.0) * 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(lf);
  FastJets fj(jetinput, clusterAlgo, R);
  declare(fj, "Jets");

  book(_h_W_jet1_deta, "W_jet1_deta", 50, -5.0, 5.0);
  book(_h_W_jet1_dR, "W_jet1_dR", 25, 0.5, 7.0);

  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
  const Particles& ls = apply<LeptonFinder>(event, "Leptons").particles();
  const int ifound = closestMatchIndex(ls, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);
  if (ifound < 0) vetoEvent;
  const Particle& l = ls[ifound];
  FourMomentum wmom = l.mom() + pmiss;

  const Jets& jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > _jetptcut);
  if (jets.size() > 0) {
    _h_W_jet1_deta->fill(wmom.eta() - jets[0].eta());
    _h_W_jet1_dR->fill(deltaR(wmom, jets[0].momentum()));
  }

  MC_JETS_BASE::analyze(event);
}


/// Finalize
void finalize() {
  scale(_h_W_jet1_deta, crossSection() / picobarn / sumOfWeights());
  scale(_h_W_jet1_dR, crossSection() / picobarn / sumOfWeights());
  MC_JETS_BASE::finalize();
}

/// @}

protected:

/// @name Parameters for specialised e/mu and dressed/bare subclassing
/// @{
double _dR;
PdgId _lepton;
/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr _h_W_jet1_deta;
Histo1DPtr _h_W_jet1_dR;
/// @}

};

RIVET_DECLARE_PLUGIN(MC_WJETS);

} ```