Rivet analyses

title: CMS_2015_I1380605

Per-event yield of the highest transverse momentum charged particle and charged-particle jet

Experiment: CMS (LHC)

Inspire ID: 1380605

Status: VALIDATED

Authors: - Anastasia Grebenyuk - Hannes Jung

References: - arXiv: 1507.00233

Beams: p+ p+

Beam energies: (4000.0, 4000.0)GeV

Run details: - $sqrt{s}=8$ TeV, minbias events, no pT cut on partons

The per-event yield of the highest transverse momentum charged particle and charged-particle jet, integrated above a given $p_{T~min}$ threshold starting at $p_{T~min}=0.8$ and $1$~GeV, respectively, is studied in $pp$ collisions at $\sqrt{s} = 8$~\TeV. The particles and the jets are measured in the pseudorapidity ranges $|\eta| < 2.4$ and $1.9$, respectively.

Source code:CMS_2015_I1380605.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

/// Per-event yield of the highest transverse momentum charged particle and charged-particle jet class CMS_2015_I1380605 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2015_I1380605);


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

/// Book histograms and initialise projections before the run
void init() {
  const ChargedFinalState cfs((Cuts::etaIn(-7., 7.)));
  declare(cfs, "CFS");
  declare(FastJets(cfs, JetAlg::ANTIKT, 0.5), "Jets");

  book(_h_tracks, 1, 1, 1);
  book(_h_jets, 2, 1, 1);
  book(_ntracks, "ntracks");
}


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

  // Veto events without forward activity on both sides
  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  const size_t count_plus = cfs.particles(Cuts::eta > 5.3 && Cuts::eta < 6.5).size();
  const size_t count_minus = cfs.particles(Cuts::eta < -5.3 && Cuts::eta > -6.5).size();
  if (!(count_plus > 0 || count_minus > 0))
    vetoEvent; //< @todo Should this really also veto the jet analysis?
  /// @warning Needs migration to an AO Counter
  /// @note This isn't the number of tracks, it's the sum of event weights passing the veto
  _ntracks->fill();

  // Do track analysis here
  // Find pttrackmax
  double track_ptmax = 0;
  for (const Particle& p : cfs.particles(Cuts::abseta < 2.4)) track_ptmax = max(track_ptmax, p.pT());
  // Fill track analysis histograms
  for (size_t i = 1; i <= _h_tracks->numBins(); ++i) {
    const double binlimitlow_t = _h_tracks->bin(i).xMin();
    const double weightbw_t = _h_tracks->bin(i).xWidth();
    const double xbin_t = _h_tracks->bin(i).xMid();
    if (track_ptmax > binlimitlow_t) _h_tracks->fill(xbin_t, weightbw_t);
  }

  // Do jet analysis here
  const Jets jetsdeta = apply<FastJets>(event, "Jets")
                            .jets(Cuts::pT > 1 * GeV && Cuts::pT < 60 * GeV && Cuts::abseta < 1.9);
  // Find ptjetmax
  double jet_ptmax = 0;
  for (const Jet& j : jetsdeta) jet_ptmax = max(jet_ptmax, j.pT());
  // Fill jet analysis histograms
  for (size_t i = 1; i <= _h_jets->numBins(); ++i) {
    const double binlimitlow_j = _h_jets->bin(i).xMin();
    const double weightbw_j = _h_jets->bin(i).xWidth();
    const double xbin_j = _h_jets->bin(i).xMid();
    if (jet_ptmax > binlimitlow_j) _h_jets->fill(xbin_j, weightbw_j);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  const double norm_t0 = _h_tracks->bin(8).sumW() / 2.056170e-03 / _h_tracks->bin(8).xWidth();
  //const double norm_t1 = _h_tracks->bin(7).sumW()/2.056170e-03;
  const double norm_j0 = _h_jets->bin(14).sumW() / 3.575290e-03 / _h_jets->bin(14).xWidth();
  //const double norm_j1 = _h_jets->bin(13).sumW()/3.575290e-03;
  if (norm_t0 > 0) scale(_h_tracks, 1. / norm_t0);
  if (norm_j0 > 0) scale(_h_jets, 1. / norm_j0);
}

/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr _h_tracks, _h_jets;
CounterPtr _ntracks;
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2015_I1380605);

} ```