Rivet analyses

e⁺e⁻ → K⁺K⁻π⁰ cross section between 2 and 3.08 GeV

Experiment: BESIII (BEPC)

Inspire ID: 2033007

Status: VALIDATED

Authors: - Peter Richardson

References: - arXiv: 2202.06447

Beams: e+ e-

Beam energies: (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.2, 1.2); (1.2, 1.2); (1.2, 1.2); (1.3, 1.3); (1.3, 1.3); (1.4, 1.4); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5)GeV

Run details: - e+e- to hadrons

Measurement of e⁺e⁻ → K⁺K⁻π⁰ cross section between 2 and 3.08 GeV. In addition the cross sections for the ϕπ⁰, K^* + K⁻ and K^*(1430)⁺K⁻.

Source code:`BESIII_2022_I2033007.cc`

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

namespace Rivet {


  /// @brief e+e- -> K+K-pi0
  class BESIII_2022_I2033007 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2033007);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(FinalState(), "FS");
      declare(UnstableParticles(), "UFS");
      // Book histograms
      for (size_t ix=0; ix<4; ++ix) {
        book(_nMeson[ix], 1+ix, 1, 1);
      }

      for (const string& en : _nMeson[0].binning().edges<0>()) {
        const double eval = stod(en);
        if (isCompatibleWithSqrtS(eval)) {
          _sqs = en; break;
        }
      }
      raiseBeamErrorIf(_sqs.empty());
    }

    void findChildren(const Particle& p, map<long,int>& nRes, int& ncount) const {
      for (const Particle& child : p.children()) {
        if (child.children().empty()) {
          nRes[child.pid()]-=1;
          --ncount;
        }
        else {
          findChildren(child,nRes,ncount);
        }
      }
    }

    /// 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 && nCount[321]==1 && nCount[-321]==1 && nCount[111]==1) _nMeson[0]->fill(_sqs);
      const FinalState& ufs = apply<FinalState>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::abspid==323 or Cuts::abspid==325 or Cuts::pid==333)) {
        if (p.children().empty()) continue;
        map<long,int> nRes = nCount;
        int ncount = ntotal;
        findChildren(p,nRes,ncount);
        if (ncount!=1) continue;
        // phi pi0
        long id = p.pid()>0 ? -321 : 321;
        if (p.pid()==333) id = 111;
        bool matched = true;
        for (const auto& val : nRes) {
          if (val.first==id) {
            if (val.second!=1) {
              matched = false;
              break;
            }
          }
          else if (val.second!=0) {
            matched = false;
            break;
          }
        }
        if (matched) {
          if (p.pid()==333)         _nMeson[1]->fill(_sqs);
          else if (p.abspid()==325) _nMeson[2]->fill(_sqs);
          else                      _nMeson[3]->fill(_sqs);
        }
      }
    }


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

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<string> _nMeson[4];
    string _sqs = "";
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BESIII_2022_I2033007);

}

Rivet analyses

e+e− → K+K−π0 cross section between 2 and 3.08 GeV

Source code:BESIII_2022_I2033007.cc

e⁺e⁻ → K⁺K⁻π⁰ cross section between 2 and 3.08 GeV

Source code:`BESIII_2022_I2033007.cc`