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- -> omega pi0pi0
 10  class BESIII_2021_I1999208 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1999208);
 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      book(_numOmegaPiPi , "TMP/OmegaPiPi");
 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    /// Perform the per-event analysis
 40    void analyze(const Event& event) {
 41      const FinalState& fs = apply<FinalState>(event, "FS");
 42      map<long,int> nCount;
 43      int ntotal(0);
 44      for (const Particle& p : fs.particles()) {
 45	nCount[p.pid()] += 1;
 46	++ntotal;
 47      }
 48      const FinalState& ufs = apply<FinalState>(event, "UFS");
 49      for (const Particle& p : ufs.particles(Cuts::pid==223)) {
 50     	if(p.children().empty()) continue;
 51	map<long,int> nRes = nCount;
 52	int ncount = ntotal;
 53	findChildren(p,nRes,ncount);
 54	if(ncount!=2) continue;	    
 55	bool matched = true;
 56	for(auto const & val : nRes) {
 57	  if(abs(val.first)==111) {
 58	    if(val.second !=2) {
 59	      matched = false;
 60	      break;
 61	    }
 62	  }
 63	  else if(val.second!=0) {
 64	    matched = false;
 65	    break;
 66	  }
 67	}
 68	if(matched) {
 69	  _numOmegaPiPi->fill();
 70	  break;
 71	}
 72      }
 73    }
 74
 75
 76    /// Normalise histograms etc., after the run
 77    void finalize() {
 78      double sigma = _numOmegaPiPi->val()* crossSection()/ sumOfWeights() /picobarn;
 79      double error = _numOmegaPiPi->err()* crossSection()/ sumOfWeights() /picobarn;
 80      Estimate1DPtr  mult;
 81      book(mult, 1, 1, 1);
 82      for (auto& b : mult->bins()) {
 83        if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
 84          b.set(sigma, error);
 85        }
 86      }
 87    }
 88
 89    /// @}
 90
 91
 92    /// @name Histograms
 93    /// @{
 94    CounterPtr _numOmegaPiPi;
 95    /// @}
 96
 97
 98  };
 99
100
101  RIVET_DECLARE_PLUGIN(BESIII_2021_I1999208);
102
103}