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CRYSTAL_BALL_1986_I238081

Measurement of $R$ and $D^*$ production for energies between 3.67 and 4.5 GeV.
Experiment: CRYSTAL_BALL (Spear)
Inspire ID: 238081
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • https://doi.org/10.17182/hepdata.18759
Beams: e- e+
Beam energies: ANY
Run details:
  • e+ e- to hadrons and e+ e- to mu+ mu- (for normalization)

Measurement of $R$ in $e^+e^-$ collisions by the Crystal Ball experiment for energies between 3.67 and 4.5 GeV. The cross section for $D^*$ production is also measured. The individual hadronic and muonic cross sections are also outputted to the yoda file so that ratio $R$ can be recalcuated if runs are combined.

Source code: CRYSTAL_BALL_1986_I238081.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 e+e- > hadrons
 10  class CRYSTAL_BALL_1986_I238081 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(CRYSTAL_BALL_1986_I238081);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      // Initialise and register projections
 23      declare(FinalState(), "FS");
 24      declare(UnstableParticles(), "UFS");
 25
 26      // Book histograms
 27      book(_c_hadrons, "/TMP/sigma_hadrons",refData<YODA::BinnedEstimate<string>>(1,1,1));
 28      book(_c_muons,   "/TMP/sigma_muons"  ,refData<YODA::BinnedEstimate<string>>(1,1,1));
 29      book(_c_D_star,  "/TMP/sigma_D_star" ,refData(2,1,1));
 30      
 31      for (const string& ecms : _c_hadrons.binning().edges<0>()) {
 32        if (isCompatibleWithSqrtS(std::stod(ecms)*GeV)) {
 33          _ecms = ecms;
 34          break;
 35        }
 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
 44      map<long,int> nCount;
 45      int ntotal(0);
 46      for (const Particle& p : fs.particles()) {
 47	nCount[p.pid()] += 1;
 48	++ntotal;
 49      }
 50      // mu+mu- + photons
 51      if(!_ecms.empty()) {
 52        if(nCount[-13]==1 and nCount[13]==1 &&
 53           ntotal==2+nCount[22])
 54          _c_muons->fill(_ecms);
 55        // everything else
 56        else
 57          _c_hadrons->fill(_ecms);
 58      }
 59      const FinalState& ufs = apply<UnstableParticles>(event, "UFS");
 60      bool found = false;
 61      for (const Particle & p : ufs.particles()) {
 62	if(abs(p.pid())!=413 && abs(p.pid())!=423) continue;
 63	bool fs = true;
 64	for (const Particle & child : p.children()) {
 65	  if(child.pid()==p.pid()) {
 66	    fs = false;
 67	    break;
 68	  }
 69	}
 70	if(fs) {
 71	  found = true;
 72	  break;
 73	}
 74      }
 75      if(found)
 76	_c_D_star->fill(sqrtS());
 77    }
 78
 79
 80    /// Normalise histograms etc., after the run
 81    void finalize() {
 82      // R
 83      BinnedEstimatePtr<string> tmp;
 84      book(tmp,1,1,1);
 85      divide(_c_hadrons,_c_muons,tmp);
 86      double fact = crossSection()/ sumOfWeights() /nanobarn;
 87      scale(_c_D_star,fact);
 88      Estimate1DPtr tmp2;
 89      book(tmp2,2,1,1);
 90      barchart(_c_D_star,tmp2);
 91    }
 92
 93    /// @}
 94
 95
 96    /// @name Histograms
 97    /// @{
 98    BinnedHistoPtr<string> _c_hadrons, _c_muons;
 99    Histo1DPtr _c_D_star;
100    string _ecms;
101    /// @}
102
103
104  };
105
106
107  RIVET_DECLARE_PLUGIN(CRYSTAL_BALL_1986_I238081);
108
109
110}