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BESIII_2014_I1323621

Cross section for $e^+e^-\to \omega\chi_{c0}$ at energies between 4.21 and 4.42 GeV
Experiment: BESIII (BEPC)
Inspire ID: 1323621
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys. Rev. D 99, 091103 (2019)
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+e- to hadrons

Measurement of the cross section for $e^+e^-\to \omega\chi_{c0}$ at energies between 4.21 and 4.42 GeV by the BESIII collaboration.

Source code: BESIII_2014_I1323621.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// @brief Cross section for $e^+e^-\to \omega\chi_{c0}$ at energies between 4.21 and 4.42 GeV
 10  class BESIII_2014_I1323621 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2014_I1323621);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      declare(FinalState(), "FS");
 23      declare(UnstableParticles(), "UFS");
 24      book(_nChi0, "TMP/chi0");
 25    }
 26
 27
 28    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 29      for( const Particle &child : p.children()) {
 30        if(child.children().empty()) {
 31          --nRes[child.pid()];
 32          --ncount;
 33        }
 34        else
 35          findChildren(child,nRes,ncount);
 36      }
 37    }
 38
 39
 40    /// Perform the per-event analysis
 41    void analyze(const Event& event) {
 42      const FinalState& fs = apply<FinalState>(event, "FS");
 43      map<long,int> nCount;
 44      int ntotal(0);
 45      for (const Particle& p :  fs.particles()) {
 46        nCount[p.pid()] += 1;
 47        ++ntotal;
 48      }
 49      const FinalState& ufs = apply<FinalState>(event, "UFS");
 50      bool matched = false;
 51      for (const Particle& p :  ufs.particles(Cuts::pid==10441)) {
 52        if(p.children().empty()) continue;
 53        map<long,int> nRes = nCount;
 54        int ncount = ntotal;
 55        findChildren(p,nRes,ncount);
 56        for (const Particle& p2 :  ufs.particles(Cuts::pid==223)) {
 57          map<long,int> nRes2 = nRes;
 58          int ncount2 = ncount;
 59          findChildren(p2,nRes2,ncount2);
 60          if(ncount2!=0) continue;
 61          matched=true;
 62          for(auto const & val : nRes2) {
 63            if(val.second!=0) {
 64              matched = false;
 65              break;
 66            }
 67          }
 68          if(matched) {
 69            _nChi0->fill();
 70            break;
 71          }
 72        }
 73        if(matched) break;
 74      }
 75    }
 76
 77
 78    /// Normalise histograms etc., after the run
 79    void finalize() {
 80      double fact =  crossSection()/ sumOfWeights() /picobarn;
 81      double sigma = _nChi0->val()*fact;
 82      double error = _nChi0->err()*fact;
 83      Estimate1DPtr  mult;
 84      book(mult, 1, 1, 1);
 85      for (auto& b : mult->bins()) {
 86        if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
 87          b.set(sigma, error);
 88        }
 89      }
 90    }
 91
 92    /// @}
 93
 94
 95    /// @name Histograms
 96    /// @{
 97    CounterPtr _nChi0;
 98    /// @}
 99
100
101  };
102
103
104  RIVET_DECLARE_PLUGIN(BESIII_2014_I1323621);
105
106}