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      Scatter2D temphisto(refData(1, 1, 1));
 81      Scatter2DPtr  mult;
 82      book(mult, 1, 1, 1);
 83      for (size_t b = 0; b < temphisto.numPoints(); b++) {
 84	const double x  = temphisto.point(b).x();
 85	pair<double,double> ex = temphisto.point(b).xErrs();
 86	pair<double,double> ex2 = ex;
 87	if(ex2.first ==0.) ex2. first=0.0001;
 88	if(ex2.second==0.) ex2.second=0.0001;
 89	if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
 90	  mult->addPoint(x, sigma, ex, make_pair(error,error));
 91	}
 92	else {
 93	  mult->addPoint(x, 0., ex, make_pair(0.,.0));
 94	}
 95      }
 96    }
 97
 98    /// @}
 99
100
101    /// @name Histograms
102    /// @{
103    CounterPtr _numOmegaPiPi;
104    /// @}
105
106
107  };
108
109
110  RIVET_DECLARE_PLUGIN(BESIII_2021_I1999208);
111
112}