Rivet analyses

Cross-sections for light hadrons at 3.773, 3.650 and 3.6648 GeV

Experiment: BESII (BEPC II)

Inspire ID: 801210

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B670 (2008) 184-189, 2008

Beams: e+ e-

Beam energies: (1.9, 1.9); (1.8, 1.8); (1.8, 1.8)GeV

Run details: - e+e- to hadrons

Cross section for e⁺e⁻ → π⁺π⁻, K⁺K⁻, 2π⁺2π⁻, K⁺K⁻π⁺π⁻ and 3π⁺3π⁻ together with a π⁰π⁰ pair at 3.773, 3.650 and 3.6648 GeV.

Source code:`BESII_2008_I801210.cc`

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

namespace Rivet {


  /// @brief Cross-sections for light hadrons at 3.773, 3.650 and 3.6648 GeV
  class BESII_2008_I801210 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2008_I801210);


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

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

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

      // Book histograms
      for (size_t ix=1; ix<6; ++ix) {
        book(_nMeson[ix], 1, 1, ix);
      }
      for (const string& en : _nMeson[1].binning().edges<0>()) {
        const double eval = stod(en);
        if (isCompatibleWithSqrtS(eval)) {
          _sqs = en; break;
        }
      }
      raiseBeamErrorIf(_sqs.empty());
    }


    /// 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 (nCount[111]!=2) vetoEvent;

      if (ntotal==4) {
        if (nCount[211]==1 && nCount[-211]==1)       _nMeson[1]->fill(_sqs);
        else if (nCount[321]==1 && nCount[-321]==1)  _nMeson[2]->fill(_sqs);
      }
      else if (ntotal==6) {
        if (nCount[211]==2 && nCount[-211]==2) _nMeson[3]->fill(_sqs);
        else if (nCount[321]==1 && nCount[-321]==1 &&
                 nCount[211]==1 && nCount[-211]==1) _nMeson[4]->fill(_sqs);
      }
      else if (ntotal==8) {
        if (nCount[211]==3 && nCount[-211]==3) _nMeson[5]->fill(_sqs);
      }

    }


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

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _nMeson[6];
    string _sqs = "";
    /// @}


  };



  RIVET_DECLARE_PLUGIN(BESII_2008_I801210);

}

Rivet analyses

Cross-sections for light hadrons at 3.773, 3.650 and 3.6648 GeV

Source code:BESII_2008_I801210.cc

Source code:`BESII_2008_I801210.cc`