1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief e+e- > pi+pi-
 9  class CMD2_2000_I511375 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(CMD2_2000_I511375);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21
22      // Initialise and register projections
23      declare(FinalState(), "FS");
24
25      // Book histograms
26      book(_npion, 1, 1, 1);
27      for (const string& en : _npion.binning().edges<0>()) {
28        const size_t idx = en.find("-");
29        if(idx!=std::string::npos) {
30          const double emin = std::stod(en.substr(0,idx));
31          const double emax = std::stod(en.substr(idx+1,string::npos));
32          if(inRange(sqrtS()/GeV, emin, emax)) {
33            _ecms = en;
34            break;
35          }
36        }
37        else {
38          const double end = std::stod(en)*GeV;
39          if (isCompatibleWithSqrtS(end)) {
40            _ecms = en;
41            break;
42          }
43        }
44      }
45      if (_ecms.empty())
46        MSG_ERROR("Beam energy incompatible with analysis.");
47    }
48
49
50    /// Perform the per-event analysis
51    void analyze(const Event& event) {
52      const FinalState& fs = apply<FinalState>(event, "FS");
53      if(fs.particles().size()!=4) vetoEvent;
54      for (const Particle& p : fs.particles()) {
55	if(abs(p.pid())!=PID::PIPLUS) vetoEvent;
56      }
57      _npion->fill(_ecms);
58
59    }
60
61
62    /// Normalise histograms etc., after the run
63    void finalize() {
64      scale(_npion, crossSection()/ sumOfWeights() /nanobarn);
65    }
66
67    /// @}
68
69
70    /// @name Histograms
71    /// @{
72    BinnedHistoPtr<string> _npion;
73    string _ecms;
74    /// @}
75
76
77  };
78
79
80  RIVET_DECLARE_PLUGIN(CMD2_2000_I511375);
81
82
83}