Rivet analyses

π0 and η spectra at 91 GeV

Experiment: L3 ()

Inspire ID: 374698

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 328 (1994) 223-233

Beams: e+ e-

Beam energies: (45.6, 45.6)GeV

Run details: - e+e- -> hadrons

Measurement of the momentum distribution of the π0 and η mesons at 91.2 GeV in e+e− collisions by the L3 collaboration.

Source code:L3_1994_I374698.cc

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

namespace Rivet {


  /// @brief pi0 and eta spectra at 91 GeV
  class L3_1994_I374698 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(L3_1994_I374698);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(UnstableParticles(), "UFS");
      // book histos
      book(_h_pi0_x_P, 5, 1, 1);
      book(_h_pi0_x_H, 6, 1, 1);
      book(_h_pi0_xi, 7, 1, 1);
      book(_h_eta_x_P, 8, 1, 1);
      book(_h_eta_x_H, 9, 1, 1);
      book(_h_eta_xi, 10, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::pid == PID::PI0 || Cuts::pid == PID::ETA)) {
        const double x = 2. * p.momentum().p3().mod() / sqrtS();
        if (p.pid() == PID::PI0) {
          _h_pi0_x_P->fill(x);
          _h_pi0_x_H->fill(x);
          _h_pi0_xi->fill(-log(x));
        }
        else {
          _h_eta_x_P->fill(x);
          _h_eta_x_H->fill(x);
          _h_eta_xi->fill(-log(x));
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_pi0_x_P, 1. / sumOfWeights());
      scale(_h_pi0_x_H, 1. / sumOfWeights());
      scale(_h_pi0_xi, 1. / sumOfWeights());
      scale(_h_eta_x_P, 1. / sumOfWeights());
      scale(_h_eta_x_H, 1. / sumOfWeights());
      scale(_h_eta_xi, 1. / sumOfWeights());
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_pi0_x_P, _h_pi0_x_H, _h_pi0_xi;
    Histo1DPtr _h_eta_x_P, _h_eta_x_H, _h_eta_xi;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(L3_1994_I374698);

}