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 e+e- -> 4 pions
 11  class CMD2_1999_I483994 : public Analysis {
 12  public:
 13
 14    /// Constructor
 15    RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_1999_I483994);
 16
 17
 18    /// @name Analysis methods
 19    /// @{
 20
 21    /// Book histograms and initialise projections before the run
 22    void init() {
 23      // Initialise and register projections
 24      declare(FinalState(), "FS");
 25      declare(UnstableParticles(), "UFS");
 26      book(_ncharged, 1, 1, 1);
 27      book(_nneutral, 2, 1, 1);
 28      book(_nomega  , 3, 1, 1);
 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      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      if(ntotal==4) {
 53	if( nCount[211] == 2 && nCount[-211] == 2 )
 54	  _ncharged->fill(round(sqrtS()/MeV));
 55	else if( nCount[211] == 1 && nCount[-211] == 1 && nCount[111] == 2)
 56	  _nneutral->fill(round(sqrtS()/MeV));
 57      }
 58
 59
 60      const FinalState& ufs = apply<FinalState>(event, "UFS");
 61      for (const Particle& p : ufs.particles()) {
 62	if(p.children().empty()) continue;
 63	// find the omega
 64	if(p.pid()==223) {
 65	  map<long,int> nRes = nCount;
 66	  int ncount = ntotal;
 67	  findChildren(p,nRes,ncount);
 68	  // omega pi+pi-
 69	  if(ncount!=1) continue;
 70	  bool matched = true;
 71	  for(auto const & val : nRes) {
 72	    if(abs(val.first)==111) {
 73	      if(val.second !=1) {
 74		matched = false;
 75		break;
 76	      }
 77	    }
 78	    else if(val.second!=0) {
 79	      matched = false;
 80	      break;
 81	    }
 82	  }
 83	  if(matched)
 84	    _nomega->fill(round(sqrtS()/MeV));
 85	}
 86      }
 87    }
 88
 89
 90    /// Normalise histograms etc., after the run
 91    void finalize() {
 92      double fact = crossSection()/ sumOfWeights() /nanobarn;
 93      scale(_ncharged,fact);
 94      scale(_nneutral,fact);
 95      scale(_nomega  ,fact);
 96    }
 97
 98    /// @}
 99
100
101    /// @name Histograms
102    /// @{
103    BinnedHistoPtr<int> _ncharged,_nneutral,_nomega;
104    /// @}
105
106
107  };
108
109
110  RIVET_DECLARE_PLUGIN(CMD2_1999_I483994);
111
112
113}