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- -> p pbar eta/omega
 10  class BESIII_2021_I1845443 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1845443);
 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(_nEta, "/TMP/nEta" );
 26      book(_nOmega, "/TMP/nOmega" );
 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      // total hadronic and muonic cross sections
 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      // find the eta/omega
 51      const FinalState& ufs = apply<UnstableParticles>(event, "UFS");
 52      for(const Particle& p : ufs.particles(Cuts::pid==PID::ETA or Cuts::pid==PID::OMEGA)) {
 53	map<long,int> nRes = nCount;
 54	int ncount = ntotal;
 55	findChildren(p,nRes,ncount);
 56	bool matched=true;
 57	for(auto const & val : nRes) {
 58	  if(abs(val.first)==PID::PROTON) {
 59	    if(val.second!=1) {
 60	      matched = false;
 61	      break;
 62	    }
 63	  }
 64	  else if(val.second!=0) {
 65	    matched = false;
 66	    break;
 67	  }
 68	}
 69	if(matched) {
 70	  if(p.pid()==PID::ETA)
 71	    _nEta->fill();
 72	  else
 73	    _nOmega->fill();
 74	  break;
 75	}
 76      }
 77    }
 78
 79
 80    /// Normalise histograms etc., after the run
 81    void finalize() {
 82      for(unsigned int ix=1;ix<3;++ix) {
 83	double sigma,error;
 84	if(ix==1) {
 85	  sigma = _nEta->val();
 86	  error = _nEta->err();
 87	}
 88	else {
 89	  sigma = _nOmega->val();
 90	  error = _nOmega->err();
 91	}
 92	sigma *= crossSection()/ sumOfWeights() /picobarn;
 93	error *= crossSection()/ sumOfWeights() /picobarn; 
 94	Scatter2D temphisto(refData(ix, 1, 1));
 95	Scatter2DPtr  mult;
 96	book(mult, ix, 1, 1);
 97	for (size_t b = 0; b < temphisto.numPoints(); b++) {
 98	  const double x  = temphisto.point(b).x();
 99	  pair<double,double> ex = temphisto.point(b).xErrs();
100	  pair<double,double> ex2 = ex;
101	  if(ex2.first ==0.) ex2. first=0.0001;
102	  if(ex2.second==0.) ex2.second=0.0001;
103	  if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
104	    mult->addPoint(x, sigma, ex, make_pair(error,error));
105	  }
106	  else {
107	    mult->addPoint(x, 0., ex, make_pair(0.,.0));
108	  }
109	}
110      }
111    }
112
113    ///@}
114
115
116    /// @name Histograms
117    ///@{
118    CounterPtr _nEta,_nOmega;
119    ///@}
120
121
122  };
123
124
125  RIVET_DECLARE_PLUGIN(BESIII_2021_I1845443);
126
127}