1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief Add a short analysis description here
 9  class BABAR_2015_I1334693 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2015_I1334693);
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(UnstableParticles(), "UFS");
24
25      // Book histograms
26      book(_h_q2 ,1, 1, 1);
27
28    }
29
30
31    // Calculate the Q2 using mother and daugher meson
32    double q2(const Particle& B, int mesonID) {
33      FourMomentum q = B.mom() - select(B.children(), Cuts::pid==mesonID)[0];
34      return q*q;
35    }
36
37    // Check for explicit decay into pdgids
38    bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
39      // Trivial check to ignore any other decays but the one in question modulo photons
40      const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
41      if (children.size()!=ids.size()) return false;
42      // Check for the explicit decay
43      return all(ids, [&](int i){return count(children, hasPID(i))==1;});
44    }
45
46    /// Perform the per-event analysis
47    void analyze(const Event& event) {
48      // Loop over D0 mesons
49      for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==PID::D0)) {
50        if (isSemileptonicDecay(p, {PID::PIMINUS, PID::POSITRON, PID::NU_E})) {
51          _h_q2->fill(q2(p, PID::PIMINUS));
52        }
53      }
54    }
55
56
57    /// Normalise histograms etc., after the run
58    void finalize() {
59
60      normalize(_h_q2, 375.4*0.3); // normalize to data
61
62    }
63
64    /// @}
65
66
67  private:
68
69
70    /// @name Histograms
71    /// @{
72    Histo1DPtr _h_q2;
73    /// @}
74
75
76  };
77
78
79  RIVET_DECLARE_PLUGIN(BABAR_2015_I1334693);
80
81
82}