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SND_2016_I1471515

Cross section for $e^+e^-\to\eta\omega\pi^0$ for energies below 2 GeV
Experiment: SND ()
Inspire ID: 1471515
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Phys.Rev. D94 (2016) no.9, 092002
Beams: e+ e-
Beam energies: ANY
Run details:
  • e+ e- to hadrons

Cross section for $e^+e^-\to\eta\omega\pi^0$ for energies below 2 GeV

Source code: SND_2016_I1471515.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 Add a short analysis description here
 10  class SND_2016_I1471515 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(SND_2016_I1471515);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22
 23      // Initialise and register projections
 24      declare(FinalState(), "FS");
 25      declare(UnstableParticles(), "UFS");
 26      book(_nOmegaEtaPi, "/TMP/nOmegaEtaPi");
 27    }
 28
 29    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 30      for (const Particle &child : p.children()) {
 31	if(child.children().empty()) {
 32	  nRes[child.pid()]-=1;
 33	  --ncount;
 34	}
 35	else
 36	  findChildren(child,nRes,ncount);
 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      for (const Particle& p : ufs.particles()) {
 51	if(p.children().empty()) continue;
 52	if(p.pid()!=223) continue;
 53	map<long,int> nRes = nCount;
 54	int ncount = ntotal;
 55	findChildren(p,nRes,ncount);
 56	for (const Particle& p2 : ufs.particles()) {
 57	  if(p2.pid()!=221) continue;
 58	  map<long,int> nResB = nRes;
 59	  int ncountB = ncount;
 60	  findChildren(p2,nResB,ncountB);
 61	  if(ncountB!=1) continue;
 62	  bool matched2 = true;
 63	  for(auto const & val : nResB) {
 64	    if(val.first==111) {
 65	      if(val.second!=1) {
 66		matched2 = false;
 67		break;
 68	      }
 69	    }
 70	    else if(val.second!=0) {
 71	      matched2 = false;
 72	      break;
 73	    }
 74	  }
 75	  if(matched2) {
 76	    _nOmegaEtaPi->fill();
 77	    break;
 78	  }
 79	}
 80      }
 81    }
 82
 83    /// Normalise histograms etc., after the run
 84    void finalize() {
 85      double sigma = _nOmegaEtaPi->val();
 86      double error = _nOmegaEtaPi->err();
 87      sigma *= crossSection()/ sumOfWeights() /nanobarn;
 88      error *= crossSection()/ sumOfWeights() /nanobarn;
 89      Estimate1DPtr mult;
 90      book(mult, 1, 1, 6);
 91      for (auto& b : mult->bins()) {
 92        if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
 93          b.set(sigma, error);
 94        }
 95      }
 96    }
 97
 98    /// @}
 99
100
101    /// @name Histograms
102    /// @{
103    CounterPtr _nOmegaEtaPi;
104    /// @}
105
106
107  };
108
109
110  RIVET_DECLARE_PLUGIN(SND_2016_I1471515);
111
112
113}