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 Add a short analysis description here
 10  class CMD2_1999_I503154 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_1999_I503154);
 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(_numEtaGamma, "TMP/EtaGamma");
 27    }
 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
 53      const FinalState& ufs = apply<FinalState>(event, "UFS");
 54      for (const Particle& p : ufs.particles()) {
 55	if(p.children().empty()) continue;
 56	// find the omega
 57	if(p.pid()==221) {
 58	  map<long,int> nRes = nCount;
 59	  int ncount = ntotal;
 60	  findChildren(p,nRes,ncount);
 61	  // eta pi+pi-
 62	  if(ncount!=1) continue;
 63	  bool matched = true;
 64          for(auto const & val : nRes) {
 65	    if(val.first==22) {
 66	      if(val.second !=1) {
 67		matched = false;
 68		break;
 69	      }
 70	    }
 71	    else if(val.second!=0) {
 72	      matched = false;
 73	      break;
 74	    }
 75	  }
 76	  if(matched)
 77	    _numEtaGamma->fill();
 78	}
 79      }
 80
 81    }
 82
 83
 84    /// Normalise histograms etc., after the run
 85    void finalize() {
 86      double sigma = _numEtaGamma->val();
 87      double error = _numEtaGamma->err();
 88      sigma *= crossSection()/ sumOfWeights() /nanobarn;
 89      error *= crossSection()/ sumOfWeights() /nanobarn;
 90      Estimate1DPtr mult;
 91      book(mult, 1, 1, 1);
 92      for (auto& b : mult->bins()) {
 93        if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
 94          b.set(sigma, error);
 95        }
 96      }
 97    }
 98
 99    /// @}
100
101
102    /// @name Histograms
103    /// @{
104    CounterPtr _numEtaGamma;
105    /// @}
106
107
108  };
109
110
111  RIVET_DECLARE_PLUGIN(CMD2_1999_I503154);
112
113
114}