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 BELLE_2007_I756012 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2007_I756012);
 15
 16
 17    /// @name Analysis methods
 18    /// @{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      declare(FinalState(), "FS");
 23      declare(UnstableParticles(), "UFS");
 24      book(_nJPsi, "TMP/jpsi");
 25    }
 26
 27    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
 28      for (const Particle &child : p.children()) {
 29	if(child.children().empty()) {
 30	  --nRes[child.pid()];
 31	  --ncount;
 32	}
 33	else
 34	  findChildren(child,nRes,ncount);
 35      }
 36    }
 37
 38    /// Perform the per-event analysis
 39    void analyze(const Event& event) {
 40      const FinalState& fs = apply<FinalState>(event, "FS");
 41      map<long,int> nCount;
 42      int ntotal(0);
 43      for (const Particle& p : fs.particles()) {
 44	nCount[p.pid()] += 1;
 45	++ntotal;
 46      }
 47      const FinalState& ufs = apply<FinalState>(event, "UFS");
 48      for (const Particle& p : ufs.particles()) {
 49	if(p.children().empty()) continue;
 50	if(p.pid()!=443) continue;
 51	// find the J/psi
 52	map<long,int> nRes = nCount;
 53	int ncount = ntotal;
 54	findChildren(p,nRes,ncount);
 55	// J/psi pi+pi-
 56	if(ncount!=2) continue;
 57	bool matched = true;
 58	for(auto const & val : nRes) {
 59	  if(abs(val.first)==211) {
 60	    if(val.second !=1) {
 61	      matched = false;
 62	      break;
 63	    }
 64	  }
 65	  else if(val.second!=0) {
 66	    matched = false;
 67	    break;
 68	  }
 69	}
 70	if(matched) {
 71	  _nJPsi->fill();
 72	  break;
 73	}
 74      }
 75    }
 76
 77
 78    /// Normalise histograms etc., after the run
 79    void finalize() {
 80      double sigma =  _nJPsi->val();
 81      double error = _nJPsi->err();
 82      sigma *= crossSection()/ sumOfWeights() /picobarn;
 83      error *= crossSection()/ sumOfWeights() /picobarn;
 84      Estimate1DPtr  mult;
 85      book(mult, 1, 1, 1);
 86      for (auto& b : mult->bins()) {
 87        if (inRange(sqrtS()/GeV, b.xMin(), b.xMax())) {
 88          b.set(sigma, error);
 89        }
 90      }
 91    }
 92
 93    /// @}
 94
 95
 96    /// @name Histograms
 97    /// @{
 98    CounterPtr _nJPsi;
 99    /// @}
100
101
102  };
103
104
105  RIVET_DECLARE_PLUGIN(BELLE_2007_I756012);
106
107
108}