Rivet analyses

title: ATLAS_2011_I926145

Measurement of electron and muon differential cross-section from heavy-flavour decays

Experiment: ATLAS (LHC)

Inspire ID: 926145

Status: VALIDATED

Authors: - Paul Bell - Holger Schulz

References: - Expt page: ATLAS-STDM-2011-07 - CERN-PH-EP-2011-108 - arXiv: 1109.0525

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - $pp$ to electron $+ X$ or muon $+ X$ at 7 TeV, heavy-flavour ($bb$ and $cc$) production with $B/D \to e/\mu$

Measurement of inclusive electron and muon cross sections for $7 < \pT <26$~GeV in $|\eta| <2.0$, excluding $1.37<|\eta|<1.52$, and muon cross section for $4 < \pT < 100$~GeV in $|\eta| <2.50$. The $W/Z/\gamma^*$ component must be subtracted to leave the heavy flavour contribution.

Source code:ATLAS_2011_I926145.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DileptonFinder.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/IdentifiedFinalState.hh"

include "Rivet/Projections/LeptonFinder.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/PromptFinalState.hh"

namespace Rivet {

/// @brief Measurement of electron and muon differential cross section from heavy flavour production /// /// Lepton cross-sections differential in pT /// /// @author Paul Bell, Holger Schulz class ATLAS_2011_I926145 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2011_I926145);


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

  // Electrons and muons
  Cut cuts = (Cuts::abseta < 1.37 || Cuts::absetaIn(1.52, 2.00)) && Cuts::pT > 7 * GeV;
  IdentifiedFinalState elecs(cuts, {PID::ELECTRON, PID::POSITRON});
  declare(elecs, "elecs");
  IdentifiedFinalState muons(Cuts::abseta < 2 && Cuts::pT > 7 * GeV, {PID::MUON, PID::ANTIMUON});
  declare(muons, "muons");
  IdentifiedFinalState muons_full(Cuts::abseta < 2.5 && Cuts::pT > 4 * GeV, {PID::MUON, PID::ANTIMUON});
  declare(muons_full, "muons_full");

  Cut cut20 = Cuts::abseta < 2.0;
  Cut cut25 = Cuts::abseta < 2.5;

  DileptonFinder zfinder_e(91.2 * GeV, 0.1, cut20 && Cuts::abspid == PID::ELECTRON,
                           Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_e, "DileptonFinder_e");
  DileptonFinder zfinder_mu(91.2 * GeV, 0.1, cut20 && Cuts::abspid == PID::MUON,
                            Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_mu, "DileptonFinder_mu");
  DileptonFinder zfinder_mufull(91.2 * GeV, 0.1, cut25 && Cuts::abspid == PID::MUON,
                                Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_mufull, "DileptonFinder_mufull");

  LeptonFinder ef(0.2, cut20 && Cuts::abspid == PID::ELECTRON);
  declare(ef, "WElecs");
  LeptonFinder mf(0.2, cut20 && Cuts::abspid == PID::MUON);
  declare(mf, "WMuons");
  LeptonFinder mff(0.2, cut25 && Cuts::abspid == PID::MUON);
  declare(mff, "WMuonsFull");
  declare("MET", MissingMomentum());

  // Book histograms
  book(_histPt_elecs, 1, 1, 1);
  book(_histPt_muons, 2, 1, 1);
  book(_histPt_muons_full, 3, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // Veto event if no lepton is present
  const Particles& elecs = apply<FinalState>(event, "elecs").particles();
  const Particles& muons = apply<FinalState>(event, "muons").particles();
  const Particles& muons_full = apply<FinalState>(event, "muons_full").particles();
  if (elecs.empty() && muons.empty() && muons_full.empty()) vetoEvent;

  // Z veto
  const DileptonFinder& zfinder_e = apply<DileptonFinder>(event, "DileptonFinder_e");
  const DileptonFinder& zfinder_mu = apply<DileptonFinder>(event, "DileptonFinder_mu");
  const DileptonFinder& zfinder_mufull = apply<DileptonFinder>(event, "DileptonFinder_mufull");
  if (zfinder_e.bosons().size() > 0 || zfinder_mu.bosons().size() > 0
      || zfinder_mufull.bosons().size() > 0) {
    MSG_DEBUG("Num elec Z-bosons found: " << zfinder_e.bosons().size());
    MSG_DEBUG("Num muon Z-bosons found: " << zfinder_mu.bosons().size());
    MSG_DEBUG("Num muon Z-bosons found (|eta|<2.5): " << zfinder_mufull.bosons().size());
    vetoEvent;
  }

  // W veto
  //       60.0*GeV, 100.0*GeV, 25.0*GeV, 0.2);
  const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
  const Particles& wes = apply<LeptonFinder>(event, "WElecs").particles();
  const int iefound = closestMatchIndex(wes, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);
  const Particles& wmus = apply<LeptonFinder>(event, "WMuons").particles();
  const int imfound = closestMatchIndex(wmus, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);
  const Particles& wfmus = apply<LeptonFinder>(event, "WMuonsFull").particles();
  const int ifmfound = closestMatchIndex(wfmus, pmiss, Kin::mass, 80.4 * GeV, 60 * GeV, 100 * GeV);
  if (pmiss.Et() > 25 * GeV && (iefound >= 0 || imfound >= 0 || ifmfound >= 0)) {
    MSG_DEBUG("Num elec W-bosons found: " << int(iefound >= 0));
    MSG_DEBUG("Num muon W-bosons found: " << int(imfound >= 0));
    MSG_DEBUG("Num muon W-bosons found (|eta|<2.5): " << int(ifmfound >= 0));
    vetoEvent;
  }

  // Electron histogram
  if (elecs.size() > 0) {
    for (const Particle& ele : elecs) {
      if (ele.pT() < 26.0 * GeV) _histPt_elecs->fill(ele.pT() / GeV);
    }
  }

  // Muon histogram
  if (muons.size() > 0) {
    for (const Particle& muo : muons) {
      if (muo.pT() < 26.0 * GeV) _histPt_muons->fill(muo.pT() / GeV);
    }
  }

  // Muon full histogram
  if (muons_full.size() > 0) {
    for (const Particle& muo : muons_full) {
      if (muo.pT() < 100.0 * GeV) _histPt_muons_full->fill(muo.pT() / GeV);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_histPt_elecs, crossSection() / nanobarn / sumOfWeights());
  scale(_histPt_muons, crossSection() / nanobarn / sumOfWeights());
  scale(_histPt_muons_full, crossSection() / nanobarn / sumOfWeights());
  // the last one is microbarn on HD, but cannot sync as the d02 is
  // currently missing from HD:
  //scale(_histPt_muons_full, crossSection()/microbarn/sumOfWeights());
}

private:

/// @name Histograms
/// @{
Histo1DPtr _histPt_elecs, _histPt_muons, _histPt_muons_full;
/// @}

};

RIVET_DECLARE_PLUGIN(ATLAS_2011_I926145);

} ```