Rivet analyses

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

Experiment: BABAR (PEP-II)

Inspire ID: 1937349

Status: VALIDATED

Authors: - Peter Richardson

References: - arXiv: 2110.00520

Beams: e+ e-

Beam energies: ANY

Run details: none listed

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:BABAR_2021_I1937349.cc

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

namespace Rivet {


  /// @brief e+e- -> pi+pi-pi0
  class BABAR_2021_I1937349 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2021_I1937349);


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

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

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

      book(_num3pi, "TMP/num3", refData(1, 1, 1));
    }


    /// 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) _num3pi->fill(sqrtS());
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_num3pi, crossSection() / sumOfWeights() / nanobarn);
      Estimate1DPtr tmp;
      book(tmp, 1, 1, 1);
      barchart(_num3pi, tmp);
    }

    ///@}


    /// @name Histograms
    ///@{
    Histo1DPtr _num3pi;
    ///@}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2021_I1937349);

}