Rivet analyses

Cross section for e+e−→ π+π−π0 between 0.62 and 3.5 GeV

Experiment: BELLE (KEKB)

Inspire ID: 2775022

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 110 (2024) 11, 112005 - arXiv: 2404.04915

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons, pi0 stable

Measurement of the cross section for e+e− → π+π−π0 by BaBar using radiative return for energies between 0.62 and 3.5 GeV. The contribution of the J/ψ has been subtracted.

Source code:BELLE_2024_I2775022.cc

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

namespace Rivet {


  /// @brief  e+e- -> pi+pi-pi0
  class BELLE_2024_I2775022 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2024_I2775022);


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

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

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

      for (unsigned int ix = 0; ix < 2; ++ix)
        book(_h[ix], "TMP/num_" + toString(ix + 1), refData(1 + ix, 1, 3));
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const FinalState& fs = apply<FinalState>(event, "FS");

      map<long, int> nCount;
      int ntotal(0);
      for (const Particle& p : fs.particles()) {
        nCount[p.pid()] += 1;
        ++ntotal;
      }
      if (ntotal != 3) vetoEvent;
      if (nCount[-211] == 1 && nCount[211] == 1 && nCount[111] == 1) {
        _h[0]->fill(sqrtS());
        _h[1]->fill(sqrtS());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h, crossSection() / sumOfWeights() / nanobarn);
      for (unsigned int ix = 0; ix < 2; ++ix) {
        Estimate1DPtr tmp;
        book(tmp, 1 + ix, 1, 3);
        barchart(_h[ix], tmp);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2024_I2775022);

}