Rivet analyses

Cross section for e+e → π+ππ0 between 1.04 and 1.38 GeV.

Experiment: SND (VEPP-2M)

Inspire ID: 508003

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B462 (1999) 365-370, 1999

Beams: e+ e-

Beam energies: (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.5, 0.5); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.6, 0.6); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7); (0.7, 0.7)GeV

Run details: - e+ e- to hadrons

Measurement of the cross section for e+e → π+ππ0 by SND for energies between 1.04 and 1.38 GeV.

Source code:SND_1999_I508003.cc

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


namespace Rivet {


  /// @brief e+e- -> pi+pi-pi0
  class SND_1999_I508003 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(SND_1999_I508003);


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

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

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

      book(_num3pi, 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(round(sqrtS()/MeV));

    }


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

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<int> _num3pi;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(SND_1999_I508003);


}