1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Add a short analysis description here
 9  class BESIII_2018_I1691798 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2018_I1691798);
14
15
16    /// @name Analysis methods
17    //@{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // Initialise and register projections
22      declare(FinalState(), "FS");
23      book(_nKKpi, "/TMP/nKKpi" );
24    }
25
26
27    /// Perform the per-event analysis
28    void analyze(const Event& event) {
29      const FinalState& fs = apply<FinalState>(event, "FS");
30
31      map<long,int> nCount;
32      int ntotal(0);
33      for (const Particle& p : fs.particles()) {
34	nCount[p.pid()] += 1;
35	++ntotal;
36      }
37
38      if(ntotal==3 && nCount[310]==1 &&
39	 ((nCount[ 321]=1 &&  nCount[-211] ==1) ||
40	  (nCount[-321]=1 &&  nCount[ 211] ==1)))
41	_nKKpi->fill();
42    }
43
44
45    /// Normalise histograms etc., after the run
46    void finalize() {
47      double sigma = _nKKpi->val();
48      double error = _nKKpi->err();
49      sigma *= crossSection()/ sumOfWeights() /picobarn;
50      error *= crossSection()/ sumOfWeights() /picobarn; 
51      Scatter2D temphisto(refData(1, 1, 1));
52      Scatter2DPtr  mult;
53      book(mult, 1, 1, 1);
54      for (size_t b = 0; b < temphisto.numPoints(); b++) {
55	const double x  = temphisto.point(b).x();
56	pair<double,double> ex = temphisto.point(b).xErrs();
57	pair<double,double> ex2 = ex;
58	if(ex2.first ==0.) ex2. first=0.0001;
59	if(ex2.second==0.) ex2.second=0.0001;
60	if (inRange(sqrtS()/GeV, x-ex2.first, x+ex2.second)) {
61	  mult->addPoint(x, sigma, ex, make_pair(error,error));
62	}
63	else {
64	  mult->addPoint(x, 0., ex, make_pair(0.,.0));
65	}
66      }
67    }
68
69    //@}
70
71
72    /// @name Histograms
73    //@{
74    CounterPtr _nKKpi;
75    //@}
76
77
78  };
79
80
81  // The hook for the plugin system
82  RIVET_DECLARE_PLUGIN(BESIII_2018_I1691798);
83
84
85}