Rivet analyses

title: CMS_2015_I1384119

Pseudorapidity distribution of charged hadrons in proton--proton collisions at $\sqrt{s} = 13$ TeV

Experiment: CMS (LHC)

Inspire ID: 1384119

Status: VALIDATED

Authors: - Hannes Jung

References: - arXiv: 1507.05915

Beams: p+ p+

Beam energies: (6500.0, 6500.0)GeV

Run details: - $\sqrt{s}=13$ TeV, $pp$ inelastic events, no $p_T$ cut on partons

The pseudorapidity distribution of charged hadrons in $pp$ collisions at $\sqrt{s} =13$ TeV is measured using a data sample obtained with the CMS detector, operated at zero magnetic field, at the CERN LHC. The yield of primary charged long-lived hadrons produced in inelastic $pp$ collisions is determined in the central region of the CMS pixel detector ($|eta| < 2$) using both hit pairs and reconstructed tracks.

Source code:CMS_2015_I1384119.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FinalState.hh"

namespace Rivet {

class CMS_2015_I1384119 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2015_I1384119);


/// Book histograms and initialise projections before the run
void init() {
  const FinalState fsa(Cuts::abseta < 20);
  declare(fsa, "FSA");
  const ChargedFinalState cfs(Cuts::abseta < 2);
  declare(cfs, "CFS");

  book(_hist_dNch_dEta_inel, 1, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // Apply inelastic selection (veto pp -> pp elastic events)
  const FinalState& fsa = apply<FinalState>(event, "FSA");
  if (fsa.size() <= 2) vetoEvent;

  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  for (const Particle& p : cfs.particles()) {
    const int id = p.abspid();
    // continue if particle is a proton, a kaon or a pion
    if (id == 211 || id == 321 || id == 2212) ///< @todo Use PID:: ID constants
      _hist_dNch_dEta_inel->fill(p.eta(), 1.0);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_hist_dNch_dEta_inel, 1 / sumOfWeights());
}

private:

/// Histograms
Histo1DPtr _hist_dNch_dEta_inel;

};

RIVET_DECLARE_PLUGIN(CMS_2015_I1384119);

} ```