Rivet analyses

Charged particle multiplicity in pp̄ collisions at $\sqrt{s} = 1.8~\TeV$

Experiment: E735 (Tevatron)

Inspire ID: 480349

Status: VALIDATED

Authors: - Holger Schulz - Andy Buckley

References: - Phys.Lett.B435:453-457,1998

Beams: p- p+

Beam energies: (900.0, 900.0)GeV

Run details: - QCD events, diffractive processes need to be switched on in order to fill the low multiplicity regions. The measurement was done in |η| ≲ 3.25 and was extrapolated to full phase space. However, the method of extrapolation remains unclear.

A measurement of the charged multiplicity distribution at $\sqrt{s} = 1.8~\TeV$. The analysis is reproduced to the best of abilities. There is no theory curve in the paper to compare to.

Source code:E735_1998_I480349.cc

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/ChargedFinalState.hh"

#include "Rivet/Projections/TriggerCDFRun0Run1.hh"
#include "Rivet/Projections/TriggerUA5.hh"

namespace Rivet {


  /// @brief E735 charged multiplicity in NSD-triggered events
  class E735_1998_I480349 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(E735_1998_I480349);


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

    void init() {
      // Projections
      declare(TriggerUA5(), "Trigger");
      declare(ChargedFinalState(), "FS");

      // Histo
      book(_hist_multiplicity ,1, 1, 1);
      book(_sumWTrig, "TMP/sumWtrig");

    }


    void analyze(const Event& event) {
      const bool trigger = apply<TriggerUA5>(event, "Trigger").nsdDecision();
      if (!trigger) vetoEvent;
      _sumWTrig->fill();

      const ChargedFinalState& fs = apply<ChargedFinalState>(event, "FS");
      const size_t numParticles = fs.particles().size();
      _hist_multiplicity->fill(numParticles);
    }


    void finalize() {
      scale(_hist_multiplicity, 1 / *_sumWTrig);
    }

    /// @}


  private:

    /// Weight counter
    CounterPtr _sumWTrig;

    /// Histograms
    Histo1DPtr _hist_multiplicity;

  };



  RIVET_DECLARE_ALIASED_PLUGIN(E735_1998_I480349, E735_1998_S3905616);

}

Aliases: - E735_1998_S3905616