Rivet analyses

title: CMS_2014_I1303894

Differential cross-section of $W$ bosons + jets in $pp$ collisions at $\sqrt{s}=7$ TeV

Experiment: CMS (LHC)

Inspire ID: 1303894

Status: VALIDATED

Authors: - Darin Baumgartel - Emanuela Barberis

References: - Phys. Lett. B741 (2014) 12-37 - https://inspirehep.net/record/1303894 - http://arxiv.org/abs/1406.7533

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - Run MC generators with $W$ decaying leptonically at 7 TeV CoM energy. A large number of events are required to populate the high jet multiplicity region. Suitable results can be achieved with 85M events.

A study of jet production in association with $W$ bosons has been performed, in events with the $W$ decaying to a muon. Jets are required to have $pT > 30$ GeV and $|eta| < 2.4$. Muons are required to have $pT > 25$ and $|eta| < 2.1$. Jets are only considered if they are separated from the muon by $\Delta{R} > 0.5$. Muons are dressed with photons in a cone of $0.1$ around the muon.

Source code:CMS_2014_I1303894.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/InvMassFinalState.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/PromptFinalState.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

/// @brief Differential cross-section of W bosons + jets in pp collisions at sqrt(s)=7 TeV /// /// @author Darin Baumgartel (darinb@cern.ch) /// /// Based on Rivet analysis originally created by Anil Singh (anil@cern.ch), Lovedeep Saini (lovedeep@cern.ch) class CMS_2014_I1303894 : public Analysis { public:

/// Constructor
CMS_2014_I1303894()
    : Analysis("CMS_2014_I1303894") { }


// Book histograms and initialise projections before the run
void init() {
  // Prompt leptons only, no test on nu flavour.
  // Projections
  const FinalState fs;
  declare(fs, "FS");

  MissingMomentum missing(fs);
  declare(missing, "MET");

  PromptFinalState pfs(fs);
  IdentifiedFinalState bareMuons(pfs);
  bareMuons.acceptIdPair(PID::MUON);
  LeptonFinder muonClusters(bareMuons, fs, -1); //, Cuts::open(), false, false);
  declare(muonClusters, "muonClusters");

  VetoedFinalState jetFS(fs);
  jetFS.addVetoOnThisFinalState(muonClusters);
  jetFS.vetoNeutrinos();
  FastJets jetprojection(jetFS, JetAlg::ANTIKT, 0.5);
  declare(jetprojection, "Jets");

  // Histograms
  book(_histDPhiMuJet1, 1, 1, 1);
  book(_histDPhiMuJet2, 2, 1, 1);
  book(_histDPhiMuJet3, 3, 1, 1);
  book(_histDPhiMuJet4, 4, 1, 1);

  book(_histEtaJet1, 5, 1, 1);
  book(_histEtaJet2, 6, 1, 1);
  book(_histEtaJet3, 7, 1, 1);
  book(_histEtaJet4, 8, 1, 1);

  book(_histHT1JetInc, 9, 1, 1);
  book(_histHT2JetInc, 10, 1, 1);
  book(_histHT3JetInc, 11, 1, 1);
  book(_histHT4JetInc, 12, 1, 1);

  book(_histJet30MultExc, 13, 1, 1);
  book(_histJet30MultInc, 14, 1, 1);

  book(_histPtJet1, 15, 1, 1);
  book(_histPtJet2, 16, 1, 1);
  book(_histPtJet3, 17, 1, 1);
  book(_histPtJet4, 18, 1, 1);

  // Counters
  book(_n_1jet, "n_1jet");
  book(_n_2jet, "n_2jet");
  book(_n_3jet, "n_3jet");
  book(_n_4jet, "n_4jet");
  book(_n_inclusivebinsummation, "n_inclusivebinsummation");
}


void analyze(const Event& event) {
  // Get the dressed muon
  const LeptonFinder& muonClusters = apply<LeptonFinder>(event, "muonClusters");
  int nmu = muonClusters.dressedLeptons().size();
  if (nmu < 1) vetoEvent;
  DressedLepton dressedmuon = muonClusters.dressedLeptons()[0];
  if (dressedmuon.momentum().abseta() > 2.1) vetoEvent;
  if (dressedmuon.momentum().pT() < 25.0 * GeV) vetoEvent;

  // Check that the muon and neutrino are not decay products of tau
  if (dressedmuon.bareLepton().hasAncestorWith(Cuts::pid == PID::TAU)) vetoEvent;
  if (dressedmuon.bareLepton().hasAncestorWith(Cuts::pid == -PID::TAU)) vetoEvent;

  // Get the missing momentum
  const MissingMomentum& met = apply<MissingMomentum>(event, "MET");
  const double ptmet = met.visibleMomentum().pT();
  const double phimet = (-met.visibleMomentum()).phi();

  // Calculate MET and MT(mu,MET), and remove events with MT < 50 GeV
  const double ptmuon = dressedmuon.pT();
  const double phimuon = dressedmuon.phi();
  const double mt_mumet = sqrt(2 * ptmuon * ptmet * (1.0 - cos(phimet - phimuon)));

  // Remove events in MT < 50 region
  if (mt_mumet < 50 * GeV) vetoEvent;

  // Loop over jets and fill pt/eta/phi quantities in vectors
  const Jets& jets_filtered = apply<FastJets>(event, "Jets").jetsByPt();
  vector<float> finaljet_pT_list, finaljet_eta_list, finaljet_phi_list;
  double htjets = 0.0;
  for (size_t ii = 0; ii < jets_filtered.size(); ++ii) {
    // Jet pT/eta/phi
    double jet_pt = jets_filtered[ii].pT();
    double jet_eta = jets_filtered[ii].eta();
    double jet_phi = jets_filtered[ii].phi();

    // Kinemetic cuts for jet acceptance
    if (fabs(jet_eta) > 2.4) continue;
    if (jet_pt < 30.0 * GeV) continue;
    if (deltaR(dressedmuon, jets_filtered[ii]) < 0.5) continue;

    // Add jet to jet list and increases the HT variable
    finaljet_pT_list.push_back(jet_pt);
    finaljet_eta_list.push_back(jet_eta);
    finaljet_phi_list.push_back(jet_phi);
    htjets += fabs(jet_pt);
  }


  // Filling of histograms:
  // Fill as many jets as there are into the exclusive jet multiplicity
  if (!finaljet_pT_list.empty()) _histJet30MultExc->fill(finaljet_pT_list.size());

  for (size_t ij = 0; ij < finaljet_pT_list.size(); ++ij) {
    _histJet30MultInc->fill(ij + 1);
    _n_inclusivebinsummation->fill();
  }

  if (finaljet_pT_list.size() >= 1) {
    _histPtJet1->fill(finaljet_pT_list[0]);
    _histEtaJet1->fill(fabs(finaljet_eta_list[0]));
    _histDPhiMuJet1->fill(deltaPhi(finaljet_phi_list[0], phimuon));
    _histHT1JetInc->fill(htjets);
    _n_1jet->fill();
  }

  if (finaljet_pT_list.size() >= 2) {
    _histPtJet2->fill(finaljet_pT_list[1]);
    _histEtaJet2->fill(fabs(finaljet_eta_list[1]));
    _histDPhiMuJet2->fill(deltaPhi(finaljet_phi_list[1], phimuon));
    _histHT2JetInc->fill(htjets);
    _n_2jet->fill();
  }

  if (finaljet_pT_list.size() >= 3) {
    _histPtJet3->fill(finaljet_pT_list[2]);
    _histEtaJet3->fill(fabs(finaljet_eta_list[2]));
    _histDPhiMuJet3->fill(deltaPhi(finaljet_phi_list[2], phimuon));
    _histHT3JetInc->fill(htjets);
    _n_3jet->fill();
  }

  if (finaljet_pT_list.size() >= 4) {
    _histPtJet4->fill(finaljet_pT_list[3]);
    _histEtaJet4->fill(fabs(finaljet_eta_list[3]));
    _histDPhiMuJet4->fill(deltaPhi(finaljet_phi_list[3], phimuon));
    _histHT4JetInc->fill(htjets);
    _n_4jet->fill();
  }
}


// Finalize the histograms.
void finalize() {

  const double inclusive_cross_section = crossSection() / picobarn;
  const double norm_1jet_histo = inclusive_cross_section * dbl(*_n_1jet) / sumOfWeights();
  const double norm_2jet_histo = inclusive_cross_section * dbl(*_n_2jet) / sumOfWeights();
  const double norm_3jet_histo = inclusive_cross_section * dbl(*_n_3jet) / sumOfWeights();
  const double norm_4jet_histo = inclusive_cross_section * dbl(*_n_4jet) / sumOfWeights();
  const double norm_incmultiplicity = inclusive_cross_section * dbl(*_n_inclusivebinsummation)
      / sumOfWeights();

  normalize(_histJet30MultExc, norm_1jet_histo);
  normalize(_histJet30MultInc, norm_incmultiplicity);

  normalize(_histPtJet1, norm_1jet_histo);
  normalize(_histHT1JetInc, norm_1jet_histo);
  normalize(_histEtaJet1, norm_1jet_histo);
  normalize(_histDPhiMuJet1, norm_1jet_histo);

  normalize(_histPtJet2, norm_2jet_histo);
  normalize(_histHT2JetInc, norm_2jet_histo);
  normalize(_histEtaJet2, norm_2jet_histo);
  normalize(_histDPhiMuJet2, norm_2jet_histo);

  normalize(_histPtJet3, norm_3jet_histo);
  normalize(_histHT3JetInc, norm_3jet_histo);
  normalize(_histEtaJet3, norm_3jet_histo);
  normalize(_histDPhiMuJet3, norm_3jet_histo);

  normalize(_histPtJet4, norm_4jet_histo);
  normalize(_histHT4JetInc, norm_4jet_histo);
  normalize(_histEtaJet4, norm_4jet_histo);
  normalize(_histDPhiMuJet4, norm_4jet_histo);
}

private:

Histo1DPtr _histJet30MultExc, _histJet30MultInc;
Histo1DPtr _histPtJet1, _histPtJet2, _histPtJet3, _histPtJet4;
Histo1DPtr _histEtaJet1, _histEtaJet2, _histEtaJet3, _histEtaJet4;
Histo1DPtr _histDPhiMuJet1, _histDPhiMuJet2, _histDPhiMuJet3, _histDPhiMuJet4;
Histo1DPtr _histHT1JetInc, _histHT2JetInc, _histHT3JetInc, _histHT4JetInc;

CounterPtr _n_1jet, _n_2jet, _n_3jet, _n_4jet, _n_inclusivebinsummation;

};

RIVET_DECLARE_PLUGIN(CMS_2014_I1303894);

} ```