Rivet analyses

title: CMS_2016_I1491953

Differential cross sections for associated production of a W boson and jets at 8 TeV

Experiment: CMS (LHC)

Inspire ID: 1491953

Status: VALIDATED

Authors: - Emanuela Barberis - B. Bhawandeep - Apichart Hortiangtham - Kadir Ocalan - Philippe Gras

References: - Phys.Rev. D95 (2017) 052002 - DOI: 10.1103/PhysRevD.95.052002 - arXiv: 1610.04222 - Expt page: CMS-SMP-14-023

Beams: p+ p+

Beam energies: (4000.0, 4000.0)GeV

Run details: - 8 TeV $pp \to W+jets$.

Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 inverse femtobarns. The W bosons are identified through their decay into a muon and a neutrino. The cross sections are reported as functions of jet multiplicity, jet transverse momenta, and the scalar sum of jet transverse momenta ($H_T$) for different jet multiplicities. Distributions of the angular correlations between the jets and the muon are examined, as well as the average number of jets as a function of $H_T$ and as a function of angular variables. The cross sections are measured in the fiducial region defined by a muon with $p_T > 25$ GeV and pseudorapidity $|\eta| < 2.1$, and by a transverse mass between the muon and the missing transverse energy $M_T > 50$ GeV. Jets are reconstructed using the anti-kT algorithm with a distance parameter R = 0.5, and only jets with $p_T > 30$ GeV, $|\eta| < 2.4$, and a separation of $\Delta R > 0.5$ from the muon are considered.

Source code:CMS_2016_I1491953.cc

```c++

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/VetoedFinalState.hh"

namespace Rivet {

/// @brief Differential cross sections for associated production of a W boson and jets at 8 TeV class CMS_2016_I1491953 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2016_I1491953);


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

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

  // Initialise and register projections
  LeptonFinder lf(0.1, Cuts::abseta < 2.4 && Cuts::abspid == PID::MUON);
  declare(lf, "Muons");
  declare(MissingMom(), "MET");

  // Define veto FS
  VetoedFinalState vfs;
  vfs.addVetoOnThisFinalState(lf);
  vfs.addVetoPairId(PID::MUON);
  vfs.vetoNeutrinos();

  FastJets fastjets(vfs, JetAlg::ANTIKT, 0.5);
  declare(fastjets, "Jets");

  book(_hist_Mult_exc, 1, 1, 1);
  book(_hist_inc_WJetMult, 2, 1, 1);

  book(_hist_addJetPt1j, 3, 1, 1);
  book(_hist_addJetPt2j, 4, 1, 1);
  book(_hist_addJetPt3j, 5, 1, 1);
  book(_hist_addJetPt4j, 6, 1, 1);

  book(_hist_addHt_1j, 7, 1, 1);
  book(_hist_addHt_2j, 8, 1, 1);
  book(_hist_addHt_3j, 9, 1, 1);
  book(_hist_addHt_4j, 10, 1, 1);

  book(_hist_diJetPt_2j, 11, 1, 1);
  book(_hist_diJetPt_3j, 12, 1, 1);
  book(_hist_diJetPt_4j, 13, 1, 1);

  book(_hist_dijetM_2j, 14, 1, 1);
  book(_hist_dijetM_3j, 15, 1, 1);
  book(_hist_dijetM_4j, 16, 1, 1);

  book(_hist_Jeteta1j, 17, 1, 1);
  book(_hist_Jeteta2j, 18, 1, 1);
  book(_hist_Jeteta3j, 19, 1, 1);
  book(_hist_Jeteta4j, 20, 1, 1);

  book(_hist_dyj1j2_2j, 21, 1, 1);
  book(_hist_dyj1j2_3j, 22, 1, 1);
  book(_hist_dyj1j2_4j, 23, 1, 1);

  book(_hist_dyj1j3_3j, 24, 1, 1);
  book(_hist_dyj2j3_3j, 25, 1, 1);

  book(_hist_dyjFjB_2j, 26, 1, 1);
  book(_hist_dyjFjB_3j, 27, 1, 1);
  book(_hist_dyjFjB_4j, 28, 1, 1);

  book(_hist_dphij1j2_2j, 29, 1, 1);
  book(_hist_dphijFjB_2j, 30, 1, 1);
  book(_hist_dRj1j2_2j, 31, 1, 1);

  book(_hist_dphij1mu_1j, 32, 1, 1);
  book(_hist_dphij2mu_2j, 33, 1, 1);
  book(_hist_dphij3mu_3j, 34, 1, 1);
  book(_hist_dphij4mu_4j, 35, 1, 1);

  book(_hist_MeanNJht_1j, 36, 1, 1);
  book(_hist_MeanNJht_2j, 37, 1, 1);
  book(_hist_MeanNJdyj1j2_2j, 38, 1, 1);
  book(_hist_MeanNJdyjFjB_2j, 39, 1, 1);
}


// Define function used for filiing inc Njets histo
void _fill(Histo1DPtr& _histJetMult, vector<FourMomentum>& finaljet_list) {
  _histJetMult->fill(0);
  for (size_t i = 0; i < finaljet_list.size(); ++i) {
    if (i == 7) break;
    _histJetMult->fill(i + 1); // inclusive multiplicity
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {

  // Identify the closest-matching l+MET to m == mW
  const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
  const Particles& mus = apply<LeptonFinder>(event, "Muons").particles();
  const Particles mus_mtfilt = select(mus, [&](const Particle& m) { return mT(m, pmiss) > 0 * GeV; });
  const int ifound = closestMatchIndex(mus_mtfilt, pmiss, Kin::mass, 80.4 * GeV);

  // Make cuts on the identified mT and lepton
  if (ifound < 0) vetoEvent;
  const FourMomentum& lepton0 = mus_mtfilt[ifound].momentum();
  const double WmT = mT(pmiss, lepton0);
  if (WmT < 50.0 * GeV) vetoEvent;
  if (lepton0.abseta() > 2.1 || lepton0.pT() < 25.0 * GeV) vetoEvent;

  // Select final jets, ordered by decreasing pT
  vector<FourMomentum> finaljet_list;
  double HT = 0.0;
  const Jets jListAll = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > 30 * GeV);
  for (const Jet& j : jListAll) {
    if (j.abseta() < 2.4 && j.pT() > 30.0 * GeV && deltaR(lepton0, j) > 0.5) {
      finaljet_list.push_back(j.momentum());
      HT += j.pT();
    }
  }

  // Another jet list, sorted by increasing rapidity
  vector<FourMomentum> jListRap = finaljet_list;
  std::sort(jListRap.begin(), jListRap.end(), cmpMomByRap);

  // Multiplicity exc plot.
  if (finaljet_list.size() <= 7) {
    _hist_Mult_exc->fill(finaljet_list.size());
  }
  else if (finaljet_list.size() > 7) {
    _hist_Mult_exc->fill(7.);
  }
  // Multiplicity inc plot.
  _fill(_hist_inc_WJetMult, finaljet_list);

  if (finaljet_list.size() >= 1) {
    _hist_addJetPt1j->fill(finaljet_list[0].pT());
    _hist_Jeteta1j->fill(fabs(finaljet_list[0].eta()));
    _hist_addHt_1j->fill(HT);
    _hist_dphij1mu_1j->fill(deltaPhi(finaljet_list[0].phi(), lepton0.phi()));
    _hist_MeanNJht_1j->fill(HT, finaljet_list.size());
  }

  if (finaljet_list.size() >= 2) {
    _hist_addJetPt2j->fill(finaljet_list[1].pT());
    _hist_Jeteta2j->fill(fabs(finaljet_list[1].eta()));
    _hist_addHt_2j->fill(HT);

    _hist_dyj1j2_2j->fill(fabs(finaljet_list[0].rapidity() - finaljet_list[1].rapidity()));
    _hist_dyjFjB_2j->fill(fabs(jListRap[0].rapidity() - jListRap[jListRap.size() - 1].rapidity()));
    _hist_dphij1j2_2j->fill(deltaPhi(finaljet_list[0].phi(), finaljet_list[1].phi()));
    _hist_dphijFjB_2j->fill(deltaPhi(jListRap[0].phi(), jListRap[jListRap.size() - 1].phi()));

    _hist_dijetM_2j->fill((add(finaljet_list[0], finaljet_list[1])).mass());
    _hist_diJetPt_2j->fill((add(finaljet_list[0], finaljet_list[1])).pT());
    _hist_dRj1j2_2j->fill(deltaR(finaljet_list[0].rapidity(), finaljet_list[0].phi(),
                                 finaljet_list[1].rapidity(), finaljet_list[1].phi()));

    _hist_dphij2mu_2j->fill(deltaPhi(finaljet_list[1].phi(), lepton0.phi()));

    _hist_MeanNJht_2j->fill(HT, finaljet_list.size());
    _hist_MeanNJdyj1j2_2j->fill(fabs(finaljet_list[0].rapidity() - finaljet_list[1].rapidity()),
                                finaljet_list.size());
    _hist_MeanNJdyjFjB_2j->fill(fabs(jListRap[0].rapidity() - jListRap[jListRap.size() - 1].rapidity()),
                                finaljet_list.size());
  }

  if (finaljet_list.size() >= 3) {
    _hist_addJetPt3j->fill(finaljet_list[2].pT());
    _hist_Jeteta3j->fill(fabs(finaljet_list[2].eta()));
    _hist_addHt_3j->fill(HT);

    _hist_dyj1j2_3j->fill(fabs(finaljet_list[0].rapidity() - finaljet_list[1].rapidity()));
    _hist_dyj1j3_3j->fill(fabs(finaljet_list[0].rapidity() - finaljet_list[2].rapidity()));
    _hist_dyj2j3_3j->fill(fabs(finaljet_list[1].rapidity() - finaljet_list[2].rapidity()));
    _hist_dyjFjB_3j->fill(fabs(jListRap[0].rapidity() - jListRap[jListRap.size() - 1].rapidity()));

    _hist_dijetM_3j->fill((add(finaljet_list[0], finaljet_list[1])).mass());
    _hist_diJetPt_3j->fill((add(finaljet_list[0], finaljet_list[1])).pT());

    _hist_dphij3mu_3j->fill(deltaPhi(finaljet_list[2].phi(), lepton0.phi()));
  }

  if (finaljet_list.size() >= 4) {
    _hist_addJetPt4j->fill(finaljet_list[3].pT());
    _hist_Jeteta4j->fill(fabs(finaljet_list[3].eta()));
    _hist_addHt_4j->fill(HT);

    _hist_dyj1j2_4j->fill(fabs(finaljet_list[0].rapidity() - finaljet_list[1].rapidity()));
    _hist_dyjFjB_4j->fill(fabs(jListRap[0].rapidity() - jListRap[jListRap.size() - 1].rapidity()));

    _hist_dijetM_4j->fill((add(finaljet_list[0], finaljet_list[1])).mass());
    _hist_diJetPt_4j->fill((add(finaljet_list[0], finaljet_list[1])).pT());
    _hist_dphij4mu_4j->fill(deltaPhi(finaljet_list[3].phi(), lepton0.phi()));
  }

} //void loop


/// Normalise histograms etc., after the run
void finalize() {

  const double crossec = !std::isnan(crossSectionPerEvent()) ? crossSection() : 36703 * picobarn;
  if (std::isnan(crossSectionPerEvent())) {
    MSG_INFO("No valid cross-section given, using NNLO xsec calculated by FEWZ " << crossec / picobarn
                                                                                 << " pb");
  }

  scale(_hist_Mult_exc, crossec / picobarn / sumOfWeights());
  scale(_hist_inc_WJetMult, crossec / picobarn / sumOfWeights());

  scale(_hist_addJetPt1j, crossec / picobarn / sumOfWeights());
  scale(_hist_addJetPt2j, crossec / picobarn / sumOfWeights());
  scale(_hist_addJetPt3j, crossec / picobarn / sumOfWeights());
  scale(_hist_addJetPt4j, crossec / picobarn / sumOfWeights());

  scale(_hist_Jeteta1j, crossec / picobarn / sumOfWeights());
  scale(_hist_Jeteta2j, crossec / picobarn / sumOfWeights());
  scale(_hist_Jeteta3j, crossec / picobarn / sumOfWeights());
  scale(_hist_Jeteta4j, crossec / picobarn / sumOfWeights());

  scale(_hist_addHt_1j, crossec / picobarn / sumOfWeights());
  scale(_hist_addHt_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_addHt_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_addHt_4j, crossec / picobarn / sumOfWeights());

  //-------------------------------------
  scale(_hist_dyj1j2_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_dyj1j2_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_dyj1j2_4j, crossec / picobarn / sumOfWeights());

  scale(_hist_dyjFjB_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_dyjFjB_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_dyjFjB_4j, crossec / picobarn / sumOfWeights());

  scale(_hist_dyj1j3_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_dyj2j3_3j, crossec / picobarn / sumOfWeights());

  scale(_hist_dphij1j2_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_dphijFjB_2j, crossec / picobarn / sumOfWeights());

  scale(_hist_dRj1j2_2j, crossec / picobarn / sumOfWeights());

  scale(_hist_dijetM_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_dijetM_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_dijetM_4j, crossec / picobarn / sumOfWeights());

  scale(_hist_diJetPt_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_diJetPt_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_diJetPt_4j, crossec / picobarn / sumOfWeights());

  scale(_hist_dphij1mu_1j, crossec / picobarn / sumOfWeights());
  scale(_hist_dphij2mu_2j, crossec / picobarn / sumOfWeights());
  scale(_hist_dphij3mu_3j, crossec / picobarn / sumOfWeights());
  scale(_hist_dphij4mu_4j, crossec / picobarn / sumOfWeights());
}

/// @}

private:

/// @name Histograms
/// @{

Histo1DPtr _hist_inc_WJetMult;
Histo1DPtr _hist_Mult_exc;

Histo1DPtr _hist_addJetPt1j;
Histo1DPtr _hist_addJetPt2j;
Histo1DPtr _hist_addJetPt3j;
Histo1DPtr _hist_addJetPt4j;

Histo1DPtr _hist_Jeteta1j;
Histo1DPtr _hist_Jeteta2j;
Histo1DPtr _hist_Jeteta3j;
Histo1DPtr _hist_Jeteta4j;

Histo1DPtr _hist_addHt_1j;
Histo1DPtr _hist_addHt_2j;
Histo1DPtr _hist_addHt_3j;
Histo1DPtr _hist_addHt_4j;

//-------------------------------------
Histo1DPtr _hist_dyj1j2_2j;
Histo1DPtr _hist_dyj1j2_3j;
Histo1DPtr _hist_dyj1j2_4j;

Histo1DPtr _hist_dyjFjB_2j;
Histo1DPtr _hist_dyjFjB_3j;
Histo1DPtr _hist_dyjFjB_4j;

Histo1DPtr _hist_dyj1j3_3j;
Histo1DPtr _hist_dyj2j3_3j;

Histo1DPtr _hist_dphij1j2_2j;
Histo1DPtr _hist_dphijFjB_2j;

Histo1DPtr _hist_dRj1j2_2j;

Histo1DPtr _hist_dijetM_2j;
Histo1DPtr _hist_dijetM_3j;
Histo1DPtr _hist_dijetM_4j;

Histo1DPtr _hist_diJetPt_2j;
Histo1DPtr _hist_diJetPt_3j;
Histo1DPtr _hist_diJetPt_4j;

Histo1DPtr _hist_dphij1mu_1j;
Histo1DPtr _hist_dphij2mu_2j;
Histo1DPtr _hist_dphij3mu_3j;
Histo1DPtr _hist_dphij4mu_4j;

//-------------------------------------
Profile1DPtr _hist_MeanNJht_1j;
Profile1DPtr _hist_MeanNJht_2j;
Profile1DPtr _hist_MeanNJdyj1j2_2j;
Profile1DPtr _hist_MeanNJdyjFjB_2j;

/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2016_I1491953);

} ```