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 pi0 gamma
 10  class SND_2020_I1800477 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(SND_2020_I1800477);
 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(_c_omega, "/TMP/omega");
 27      book(_c_total, "/TMP/total");
 28    }
 29
 30    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 31      for( const Particle &child : p.children()) {
 32	if(child.children().empty()) {
 33	  --nRes[child.pid()];
 34	  --ncount;
 35	}
 36	else
 37	  findChildren(child,nRes,ncount);
 38      }
 39    }
 40
 41    /// Perform the per-event analysis
 42    void analyze(const Event& event) {
 43
 44      const FinalState& fs = apply<FinalState>(event, "FS");
 45
 46      map<long,int> nCount;
 47      int ntotal(0);
 48      for (const Particle& p : fs.particles()) {
 49	nCount[p.pid()] += 1;
 50	++ntotal;
 51      }
 52      const FinalState& ufs = apply<FinalState>(event, "UFS");
 53      for (const Particle& p : ufs.particles()) {
 54	if(p.children().empty()) continue;
 55	// find the eta
 56	if(p.pid()!=221) continue;
 57	map<long,int> nRes = nCount;
 58	int ncount = ntotal;
 59	findChildren(p,nRes,ncount);
 60	// check eta pi0 gamma FS
 61	if(ncount!=2) continue;
 62	bool matched=true;
 63	for(auto const & val : nRes) {
 64	  if(abs(val.first)==22 || val.first==111 ) {
 65	    if(val.second !=1) {
 66	      matched = false;
 67	      break;
 68	    }
 69	  }
 70	  else if(val.second!=0) {
 71	    matched = false;
 72	    break;
 73	  }
 74	}
 75	if(!matched) continue;
 76	_c_total->fill();
 77	// check if from omega
 78	for (const Particle& p2 : ufs.particles()) {
 79	  if(p2.pid()!=223) continue;
 80	  map<long,int> nResB = nRes;
 81	  int ncountB = ncount;
 82	  findChildren(p2,nResB,ncountB);
 83	  if(ncountB!=0) continue;
 84	  bool matched2 = true;
 85	  for(auto const & val : nResB) {
 86	    if(val.second!=0) {
 87	      matched2 = false;
 88	      break;
 89	    }
 90	  }
 91	  if(matched2)
 92	    _c_omega->fill();
 93	}
 94      }
 95    }
 96
 97
 98    /// Normalise histograms etc., after the run
 99    void finalize() {
100      double fact = crossSection()/picobarn/sumOfWeights();
101      for(unsigned int ix=1;ix<4; ix+=2) {
102       	double sigma(0.),error(0.);
103       	if(ix==1) {
104       	  sigma = _c_omega->val()*fact;
105       	  error = _c_omega->err()*fact;
106       	}
107       	else if(ix==3) {
108       	  sigma = _c_total->val()*fact;
109       	  error = _c_total->err()*fact;
110       	}
111       	Estimate1DPtr  mult;
112       	book(mult, ix, 1, 1);
113       	for (auto& b : mult->bins()) {
114      	  if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
115      	    b.set(sigma, error);
116      	  }
117       	}
118      }
119    }
120
121    /// @}
122
123
124    /// @name Histograms
125    /// @{
126    CounterPtr _c_total,_c_omega;
127    /// @}
128
129
130  };
131
132
133  RIVET_DECLARE_PLUGIN(SND_2020_I1800477);
134
135}