Rivet analyses

title: ATLAS_2014_I1300647

Measurement of $Z/\gamma^*$ boson $p_T$ at $\sqrt{s} = 7\TeV$

Experiment: ATLAS (LHC)

Inspire ID: 1300647

Status: VALIDATED

Authors: - Elena Yatsenko

References: - Expt page: ATLAS-STDM-2012-23 - JHEP09(2014)145 - arXiv: 1406.3660

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - $Z/\gamma^*$ production with decays to electrons and/or muons.

A measurement of the $Z/\gamma^$ transverse momentum spectrum using ATLAS proton-proton collision data at a center of mass energy of $\sqrt{s} = 7{\TeV}$ at the LHC. The measurement is performed in both $Z/\gamma^ \rightarrow ee$ and $Z/\gamma^* \rightarrow \mu \mu$ channels.

Source code:`ATLAS_2014_I1300647.cc`

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DileptonFinder.hh"

include "Rivet/Projections/FinalState.hh"

/// @todo Include more projections as required, e.g. ChargedFinalState, FastJets, DileptonFinder...

namespace Rivet {

class ATLAS_2014_I1300647 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2014_I1300647);

public:

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

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

  DileptonFinder zfinder_dressed_el(91.2 * GeV, 0.1,
                                    Cuts::abseta < 2.4 && Cuts::pT > 20 * GeV
                                        && Cuts::abspid == PID::ELECTRON,
                                    Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_dressed_el, "DileptonFinder_dressed_el");

  DileptonFinder zfinder_bare_el(91.2 * GeV, 0.0,
                                 Cuts::abseta < 2.4 && Cuts::pT > 20 * GeV
                                     && Cuts::abspid == PID::ELECTRON,
                                 Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_bare_el, "DileptonFinder_bare_el");

  DileptonFinder zfinder_dressed_mu(91.2 * GeV, 0.1,
                                    Cuts::abseta < 2.4 && Cuts::pT > 20 * GeV
                                        && Cuts::abspid == PID::MUON,
                                    Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_dressed_mu, "DileptonFinder_dressed_mu");

  DileptonFinder zfinder_bare_mu(91.2 * GeV, 0.0,
                                 Cuts::abseta < 2.4 && Cuts::pT > 20 * GeV && Cuts::abspid == PID::MUON,
                                 Cuts::massIn(66.0 * GeV, 116.0 * GeV));
  declare(zfinder_bare_mu, "DileptonFinder_bare_mu");

  // Book histograms
  book(_hist_zpt_el_dressed, 1, 1, 1); // electron "dressed"
  book(_hist_zpt_mu_dressed, 1, 1, 2); // muon "dressed"
  book(_hist_zpt_el_bare, 1, 2, 1);    // electron "bare"
  book(_hist_zpt_mu_bare, 1, 2, 2);    // muon "bare"

  //double-differential plots
  book(_h_zpt_el_mu_dressed, {0., 1., 2., 2.4}, {"d03-x01-y02", "d03-x01-y04", "d03-x01-y06"});
}


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

  const DileptonFinder& zfinder_dressed_el = apply<DileptonFinder>(event, "DileptonFinder_dressed_el");
  const DileptonFinder& zfinder_bare_el = apply<DileptonFinder>(event, "DileptonFinder_bare_el");
  const DileptonFinder& zfinder_dressed_mu = apply<DileptonFinder>(event, "DileptonFinder_dressed_mu");
  const DileptonFinder& zfinder_bare_mu = apply<DileptonFinder>(event, "DileptonFinder_bare_mu");

  FillPlots1d(zfinder_dressed_el, _hist_zpt_el_dressed);

  FillPlots1d(zfinder_bare_el, _hist_zpt_el_bare);

  FillPlots1d(zfinder_dressed_mu, _hist_zpt_mu_dressed);

  FillPlots1d(zfinder_bare_mu, _hist_zpt_mu_bare);

  FillPlots3d(zfinder_dressed_el, _h_zpt_el_mu_dressed);
  FillPlots3d(zfinder_dressed_mu, _h_zpt_el_mu_dressed);
}

void FillPlots1d(const DileptonFinder& zfinder, Histo1DPtr hist) {
  if (zfinder.bosons().size() != 1) return;
  const FourMomentum pZ = zfinder.bosons()[0].momentum();
  hist->fill(pZ.pT() / GeV);
  return;
}

void FillPlots3d(const DileptonFinder& zfinder, Histo1DGroupPtr& binnedHist) {
  if (zfinder.bosons().size() != 1) return;
  const FourMomentum pZ = zfinder.bosons()[0].momentum();
  binnedHist->fill(pZ.rapidity(), pZ.pT() / GeV);
  return;
}

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

  normalize(_hist_zpt_el_dressed);
  normalize(_hist_zpt_el_bare);

  normalize(_hist_zpt_mu_dressed);
  normalize(_hist_zpt_mu_bare);

  normalize(_h_zpt_el_mu_dressed);
}

/// @}

private:

// Data members like post-cuts event weight counters go here