1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/UnstableParticles.hh"
  5
  6
  7namespace Rivet {
  8
  9
 10  /// @brief Add a short analysis description here
 11  class SND_2000_I524221 : public Analysis {
 12  public:
 13
 14    /// Constructor
 15    RIVET_DEFAULT_ANALYSIS_CTOR(SND_2000_I524221);
 16
 17
 18    /// @name Analysis methods
 19    /// @{
 20
 21    /// Book histograms and initialise projections before the run
 22    void init() {
 23
 24      // Initialise and register projections
 25      declare(FinalState(), "FS");
 26      declare(UnstableParticles(), "UFS");
 27      book(_numEtaGamma, "TMP/EtaGamma");
 28      book(_numPi0Gamma, "TMP/Pi0Gamma");
 29    }
 30
 31    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 32      for (const Particle &child : p.children()) {
 33	if(child.children().empty()) {
 34	  --nRes[child.pid()];
 35	  --ncount;
 36	}
 37	else
 38	  findChildren(child,nRes,ncount);
 39      }
 40    }
 41
 42    /// Perform the per-event analysis
 43    void analyze(const Event& event) {
 44
 45      const FinalState& fs = apply<FinalState>(event, "FS");
 46
 47      map<long,int> nCount;
 48      int ntotal(0);
 49      for (const Particle& p : fs.particles()) {
 50	nCount[p.pid()] += 1;
 51	++ntotal;
 52      }
 53      if(ntotal==2 && nCount[22]==1 && nCount[111]==1)
 54	_numPi0Gamma->fill();
 55
 56
 57      const FinalState& ufs = apply<FinalState>(event, "UFS");
 58      for (const Particle& p : ufs.particles()) {
 59	if(p.children().empty()) continue;
 60	// find the eta
 61	if(p.pid()==221) {
 62	  map<long,int> nRes = nCount;
 63	  int ncount = ntotal;
 64	  findChildren(p,nRes,ncount);
 65	  // eta pi+pi-
 66	  if(ncount!=1) continue;
 67	  bool matched = true;
 68	  for(auto const & val : nRes) {
 69	    if(val.first==22) {
 70	      if(val.second !=1) {
 71		matched = false;
 72		break;
 73	      }
 74	    }
 75	    else if(val.second!=0) {
 76	      matched = false;
 77	      break;
 78	    }
 79	  }
 80	  if(matched)
 81	    _numEtaGamma->fill();
 82	}
 83      }
 84    }
 85
 86
 87    /// Normalise histograms etc., after the run
 88    void finalize() {
 89      for (unsigned int ix=1;ix<3;++ix) {
 90        double sigma,error;
 91        if(ix==1) {
 92          sigma = _numEtaGamma->val();
 93          error = _numEtaGamma->err();
 94        }
 95        else {
 96          sigma = _numPi0Gamma->val();
 97          error = _numPi0Gamma->err();
 98        }
 99        sigma *= crossSection()/ sumOfWeights() /nanobarn;
100        error *= crossSection()/ sumOfWeights() /nanobarn;
101        Estimate1DPtr mult;
102        book(mult, 1, 1, ix);
103        for (auto& b : mult->bins()) {
104          if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
105            b.set(sigma, error);
106          }
107        }
108      }
109    }
110
111    /// @}
112
113
114    /// @name Histograms
115    /// @{
116    CounterPtr _numEtaGamma,_numPi0Gamma;
117    /// @}
118
119
120  };
121
122
123  RIVET_DECLARE_PLUGIN(SND_2000_I524221);
124
125
126}