Rivet analyses

Spectra for anti-protons and Λ̄0 at 34 GeV

Experiment: JADE (Petra)

Inspire ID: 166363

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. 104B (1981) 325-329

Beams: e+ e-

Beam energies: (17.0, 17.0)GeV

Run details: - e+ e- to hadrons

Measurement of the anti-proton and Λ̄0 momentum spectrum in e+e− collisions for a centre-of-mass energy of 34 GeV by the JADE experiment at Petra. Useful as not summed over particle and antiparticle, only the antibaryons are included.

Source code:JADE_1981_I166363.cc

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

namespace Rivet {


  /// @brief pbar and lambdabar at 34 GeV
  class JADE_1981_I166363 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(JADE_1981_I166363);


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

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

      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");

      // Book histograms
      book(_h_pbar     , 1, 1, 1);
      book(_h_lambdabar, 2, 1, 1);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // at least 5 charged FS particles
      const FinalState& fs = apply<FinalState>(event, "FS");
      const size_t numParticles = fs.particles().size();

      if (numParticles < 3) {
        MSG_DEBUG("Failed leptonic event cut");
        vetoEvent;
      }
      MSG_DEBUG("Passed leptonic event cut");

      for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==-2212 or Cuts::pid==-3122)) {
    if(p.pid()==-2212)
      _h_pbar->fill(p.p3().mod());
    else
      _h_lambdabar->fill(p.p3().mod());
      }

    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_pbar     , crossSection()/nanobarn/sumOfWeights());
      scale(_h_lambdabar, crossSection()/nanobarn/sumOfWeights());
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr  _h_pbar, _h_lambdabar;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(JADE_1981_I166363);


}