1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief e+e- -> pi+pi+pi-pi-
 9  class DM1_1979_I132828 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(DM1_1979_I132828);
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 histograms
24      book(_npion, 1, 1, 1);
25      // extract the centre-of-mass energies
26      vector<string> energies = _npion.binning().edges<0>();
27      if     (sqrtS()>=0.963 && sqrtS()<=1.002)  _ecms=energies[0];
28      else if(sqrtS()>=1.008 && sqrtS()<=1.024)  _ecms=energies[1];
29      else if(isCompatibleWithSqrtS(std::stod(energies[2])*MeV)) _ecms=energies[2];
30      else if(isCompatibleWithSqrtS(std::stod(energies[3])*MeV)) _ecms=energies[3];
31      if(_ecms.empty()) MSG_ERROR("Beam energy incompatible with analysis.");
32    }
33
34
35    /// Perform the per-event analysis
36    void analyze(const Event& event) {
37      const FinalState& fs = apply<FinalState>(event, "FS");
38      if(fs.particles().size()!=4) vetoEvent;
39      for (const Particle& p : fs.particles()) {
40        if(abs(p.pid())!=PID::PIPLUS)  vetoEvent;
41      }
42      _npion->fill(_ecms);
43    }
44
45
46    /// Normalise histograms etc., after the run
47    void finalize() {
48      scale(_npion, crossSection()/ sumOfWeights() /nanobarn);
49    }
50
51    /// @}
52
53    /// @name Histograms
54    /// @{
55    BinnedHistoPtr<string> _npion;
56    string _ecms;
57    /// @}
58
59
60  };
61
62
63  RIVET_DECLARE_PLUGIN(DM1_1979_I132828);
64
65
66}