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- > omega pi
 10  class SND_2016_I1489182 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(SND_2016_I1489182);
 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(_numOmegaPi, "TMP/OmegaPi");
 27    }
 28
 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()]+=1;
 35	  ++ncount;
 36	}
 37	else
 38	  findChildren(child,nRes,ncount);
 39      }
 40    }
 41    /// Perform the per-event analysis
 42    void analyze(const Event& event) {
 43      const FinalState& fs = apply<FinalState>(event, "FS");
 44
 45      map<long,int> nCount;
 46      int ntotal(0);
 47      for (const Particle& p : fs.particles()) {
 48	nCount[p.pid()] += 1;
 49	++ntotal;
 50      }
 51      // three particles (pi0 pi0 gamma)
 52      if(ntotal!=3) vetoEvent;
 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()==223) {
 58	  map<long,int> nRes;
 59	  int ncount(0);
 60	  findChildren(p,nRes,ncount);
 61	  // only omega to pi0 gamma mode
 62	  if(ncount!=2) continue;
 63	  if(nRes[111]!=1 || nRes[22]!=1) continue;
 64	  // omega pi0
 65	  if(nCount[111]-nRes[111]==1)
 66	    _numOmegaPi->fill();
 67	}
 68      }
 69    }
 70
 71
 72    /// Normalise histograms etc., after the run
 73    void finalize() {
 74
 75      double sigma = _numOmegaPi->val();
 76      double error = _numOmegaPi->err();
 77      sigma *= crossSection()/ sumOfWeights() /nanobarn;
 78      error *= crossSection()/ sumOfWeights() /nanobarn;
 79      Estimate1DPtr mult;
 80      book(mult, 1, 1, 1);
 81      for (auto& b : mult->bins()) {
 82        if (inRange(sqrtS()/MeV, b.xMin(), b.xMax())) {
 83          b.set(sigma, error);
 84        }
 85      }
 86    }
 87
 88    /// @}
 89
 90    /// @name Histograms
 91    /// @{
 92    CounterPtr _numOmegaPi;
 93    /// @}
 94
 95
 96  };
 97
 98
 99  RIVET_DECLARE_PLUGIN(SND_2016_I1489182);
100
101
102}