Rivet analyses

Cross-sections for light hadrons at 3.773, 3.650 GeV

Experiment: BESII (BEPC II)

Inspire ID: 750713

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B650 (2007) 111-118, 2007

Beams: e+ e-

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

Run details: - e+e- to hadrons

Cross section for e⁺e⁻ → 2π⁺2π⁻, K⁺K⁻π⁺π⁻, 2K⁺2K⁻, ϕK⁺K⁻, pp̄π⁺π⁻, pp̄K⁺K⁻, 3π⁺3π⁻, 2π⁺2π⁻η, 2π⁺2π⁻π⁰, K⁺K⁻π⁺π⁻π⁰, 2K⁺2K⁻π⁰, pp̄π⁰, pp̄π⁺π⁻π⁰, 3π⁺3π⁻π⁰ at 3.773 and 3.650 GeV.

Source code:`BESII_2007_I750713.cc`

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

namespace Rivet {


  /// @brief Cross-sections for light hadrons at 3.773, 3.650 GeV
  class BESII_2007_I750713 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESII_2007_I750713);


    /// @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
      _sqs = -1;
      if (isCompatibleWithSqrtS(3.65))
        _sqs = 100;
      else if (isCompatibleWithSqrtS(3.773))
        _sqs = 0;
      raiseBeamErrorIf(_sqs < 0);

      for (size_t ix = 3; ix < 19; ++ix) {
        if (ix == 5 || ix == 10) continue;
        book(_nMeson[ix], "TMP/n"s + toString(ix));
        book(_nMeson[ix + 100], "TMP/n"s + toString(ix + 100));
      }
    }


    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;
      }
      const FinalState& ufs = apply<FinalState>(event, "UFS");

      for (const Particle& p : ufs.particles()) {
        if (p.children().empty()) continue;
        if (p.pid() != 221 && p.pid() != 333) continue;
        map<long, int> nRes = nCount;
        int ncount = ntotal;
        findChildren(p, nRes, ncount);
        // eta
        if (p.pid() == 221) {
          if (ncount == 4) {
            bool matched = true;
            for (const auto& val : nRes) {
              if (abs(val.first) == 211) {
                if (val.second != 2) {
                  matched = false;
                  break;
                }
              }
              else if (val.second != 0) {
                matched = false;
                break;
              }
            }
            if (matched) _nMeson[12 + _sqs]->fill();
          }
        }
        else if (p.pid() == 333) {
          if (ncount != 1) continue;
          bool matched = true;
          for (const auto& val : nRes) {
            if (abs(val.first) == 321) {
              if (val.second != 1) {
                matched = false;
                break;
              }
            }
            else if (val.second != 0) {
              matched = false;
              break;
            }
          }
          if (matched) _nMeson[7 + _sqs]->fill();
        }
      }
      if (ntotal == 3 && nCount[111] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
        _nMeson[16 + _sqs]->fill();
      else if (ntotal == 4) {
        if (nCount[-211] == 2 && nCount[211] == 2)
          _nMeson[3 + _sqs]->fill();
        else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-321] == 1 && nCount[321] == 1)
          _nMeson[4 + _sqs]->fill();
        else if (nCount[-321] == 2 && nCount[321] == 2)
          _nMeson[6 + _sqs]->fill();
        else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
          _nMeson[8 + _sqs]->fill();
        else if (nCount[-321] == 1 && nCount[321] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
          _nMeson[9 + _sqs]->fill();
      }
      else if (ntotal == 5 && nCount[111] == 1) {
        if (nCount[-211] == 2 && nCount[211] == 2)
          _nMeson[13 + _sqs]->fill();
        else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-321] == 1 && nCount[321] == 1)
          _nMeson[14 + _sqs]->fill();
        else if (nCount[-321] == 2 && nCount[321] == 2)
          _nMeson[15 + _sqs]->fill();
        else if (nCount[-211] == 1 && nCount[211] == 1 && nCount[-2212] == 1 && nCount[2212] == 1)
          _nMeson[17 + _sqs]->fill();
      }
      else if (ntotal == 6 && nCount[211] == 3 && nCount[-211] == 3)
        _nMeson[11 + _sqs]->fill();
      else if (ntotal == 7 && nCount[111] == 1 && nCount[211] == 3 && nCount[-211] == 3)
        _nMeson[18 + _sqs]->fill();
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_nMeson, crossSection() / sumOfWeights() / picobarn);
      BinnedEstimatePtr<string> mult;
      for (unsigned int ix = 3; ix < 19; ++ix) {
        if (ix == 5 || ix == 10) continue;
        book(mult, 1, 1, ix);
        mult->bin(1).set(_nMeson[ix]->val(), _nMeson[ix]->err());
        if (ix != 15) mult->bin(2).set(_nMeson[ix + 100]->val(), _nMeson[ix + 100]->err());
      }
    }
    /// @}


    /// @name Histograms
    /// @{
    map<int, CounterPtr> _nMeson;
    int _sqs;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BESII_2007_I750713);

}

Rivet analyses

Cross-sections for light hadrons at 3.773, 3.650 GeV

Source code:BESII_2007_I750713.cc

Source code:`BESII_2007_I750713.cc`