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- > eta h_c
 10  class BESIII_2017_I1596897 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2017_I1596897);
 15
 16
 17    /// @name Analysis methods
 18    //@{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      declare(FinalState(), "FS");
 23      declare(UnstableParticles(), "UFS");
 24      book(_nhc, "TMP/h_c");
 25    }
 26
 27    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 28      for (const Particle &child : p.children()) {
 29	if(child.children().empty()) {
 30	  --nRes[child.pid()];
 31	  --ncount;
 32	}
 33	else
 34	  findChildren(child,nRes,ncount);
 35      }
 36    }
 37
 38    /// Perform the per-event analysis
 39    void analyze(const Event& event) {
 40      const FinalState& fs = apply<FinalState>(event, "FS");
 41      map<long,int> nCount;
 42      int ntotal(0);
 43      for (const Particle& p : fs.particles()) {
 44	nCount[p.pid()] += 1;
 45	++ntotal;
 46      }
 47      const FinalState& ufs = apply<FinalState>(event, "UFS");
 48      // loop over h_c
 49      for (const Particle& hc : ufs.particles(Cuts::pid==10443)) {
 50	if(hc.children().empty()) continue;
 51	map<long,int> nRes = nCount;
 52	int ncount = ntotal;
 53	findChildren(hc,nRes,ncount);
 54	bool matched = false;
 55	// loop over eta
 56	for(const Particle & eta : ufs.particles(Cuts::pid==221)) {
 57	  // check eta not child of h_c
 58	  Particle parent=eta;
 59	  while(!parent.parents().empty()) {
 60	    parent=parent.parents()[0];
 61	    if(parent.abspid()==10443) break;
 62	  }
 63	  if(fuzzyEquals(parent.momentum(),hc.momentum())) continue;
 64	  map<long,int> nRes2 = nRes;
 65	  int ncount2 = ncount;
 66	  findChildren(eta,nRes2,ncount2);
 67	  if(ncount2!=0) continue;
 68	  matched=true;
 69	  for(auto const & val : nRes2) {
 70	    if(val.second!=0) {
 71	      matched = false;
 72	      break;
 73	    }
 74	  }
 75	  if(matched) {
 76	    _nhc->fill();
 77	    break;
 78	  }
 79	}
 80	if(matched) break;
 81      }
 82    }
 83
 84
 85    /// Normalise histograms etc., after the run
 86    void finalize() {
 87      double sigma = _nhc->val();
 88      double error = _nhc->err();
 89      sigma *= crossSection()/ sumOfWeights() /picobarn;
 90      error *= crossSection()/ sumOfWeights() /picobarn;
 91      Scatter2D temphisto(refData(1, 1, 1));
 92      Scatter2DPtr  mult;
 93      book(mult, 1, 1, 1);
 94      for (size_t b = 0; b < temphisto.numPoints(); b++) {
 95	const double x  = temphisto.point(b).x();
 96	pair<double,double> ex = temphisto.point(b).xErrs();
 97	pair<double,double> ex2 = ex;
 98	if(ex2.first ==0.) ex2. first=0.0001;
 99	if(ex2.second==0.) ex2.second=0.0001;
100	if (inRange(sqrtS()/MeV, x-ex2.first, x+ex2.second)) {
101	  mult->addPoint(x, sigma, ex, make_pair(error,error));
102	}
103	else {
104	  mult->addPoint(x, 0., ex, make_pair(0.,.0));
105	}
106      }
107    }
108
109    //@}
110
111
112    /// @name Histograms
113    //@{
114    CounterPtr _nhc;
115    //@}
116
117
118  };
119
120
121  RIVET_DECLARE_PLUGIN(BESIII_2017_I1596897);
122
123}