1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief e+e- > pi0 pi0 gamma
 9  class KLOE_2007_I725483 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(KLOE_2007_I725483);
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      // get the CMS point
24      unsigned int ix=0;
25      if (isCompatibleWithSqrtS(1.01955))     ix=1;
26      else if(isCompatibleWithSqrtS(1.01965)) ix=2;
27      else if(isCompatibleWithSqrtS(1.01985)) ix=3;
28      else if(isCompatibleWithSqrtS(1.01995)) ix=4;
29      else throw Error("Unexpected sqrtS !");
30      for (unsigned int iy=0; iy<2; ++iy) {
31        book(_h[iy],1,ix,iy+1);
32      }
33    }
34
35
36    /// Perform the per-event analysis
37    void analyze(const Event& event) {
38      const FinalState& fs = apply<FinalState>(event, "FS");
39      Particles pi0,gamma;
40      map<long,Particles> nCount;
41      int ntotal(0);
42      for (const Particle& p : fs.particles()) {
43        if (p.pid()==PID::PI0)          pi0.push_back(p);
44        else if (p.pid()==PID::GAMMA) gamma.push_back(p);
45        ++ntotal;
46      }
47      // three particles (pi0 pi0 gamma)
48      if (ntotal!=3 || pi0.size()!=2 || gamma.size()!=1) vetoEvent;
49      _h[0]->fill((pi0[0].mom()+  pi0[1].mom()).mass()/MeV);
50      _h[1]->fill((pi0[0].mom()+gamma[0].mom()).mass()/MeV);
51      _h[1]->fill((pi0[1].mom()+gamma[0].mom()).mass()/MeV);
52    }
53
54
55    /// Normalise histograms etc., after the run
56    void finalize() {
57      normalize(_h);
58    }
59
60    /// @}
61
62
63    /// @name Histograms
64    /// @{
65    Histo1DPtr _h[2];
66    /// @}
67
68
69  };
70
71
72  RIVET_DECLARE_PLUGIN(KLOE_2007_I725483);
73
74}