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- > eta K+K-
10  class SND_2018_I1693737 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(SND_2018_I1693737);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      // Initialise and register projections
23      declare(FinalState(), "FS");
24      declare(UnstableParticles(), "UFS");
25      book(_nKKEta, "/TMP/nKKEta", refData(1,1,1));
26    }
27
28    void findChildren(const Particle & p,map<long,int> & nRes, int &ncount) {
29      for (const Particle &child : p.children()) {
30	if(child.children().empty()) {
31	  nRes[child.pid()]-=1;
32	  --ncount;
33	}
34	else
35	  findChildren(child,nRes,ncount);
36      }
37    }
38
39    /// Perform the per-event analysis
40    void analyze(const Event& event) {
41      const FinalState& fs = apply<FinalState>(event, "FS");
42      map<long,int> nCount;
43      int ntotal(0);
44      for (const Particle& p : fs.particles()) {
45	nCount[p.pid()] += 1;
46	++ntotal;
47      }
48      const FinalState& ufs = apply<FinalState>(event, "UFS");
49      for (const Particle& p : ufs.particles()) {
50      	if(p.children().empty()) continue;
51      	if(p.pid()!=221) continue;
52      	map<long,int> nRes = nCount;
53      	int ncount = ntotal;
54      	findChildren(p,nRes,ncount);
55	if(ncount!=2) continue;
56	bool matched = true;
57	for(auto const & val : nRes) {
58	  if(abs(val.first)==321) {
59	    if(val.second!=1) {
60	      matched = false;
61	      break;
62	    }
63	  }
64	  else if(val.second!=0) {
65	    matched = false;
66	    break;
67	  }
68	}
69	if(matched) {
70	  _nKKEta->fill(sqrtS());
71	  break;
72	}
73      }
74    }
75
76    /// Normalise histograms etc., after the run
77    void finalize() {
78      scale(_nKKEta, crossSection()/ sumOfWeights() /nanobarn);
79      Estimate1DPtr mult;
80      book(mult, 1, 1, 1);
81      barchart(_nKKEta,mult);
82    }
83
84    /// @}
85
86
87    /// @name Histograms
88    /// @{
89    Histo1DPtr _nKKEta;
90    /// @}
91
92
93  };
94
95
96  RIVET_DECLARE_PLUGIN(SND_2018_I1693737);
97
98
99}