1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief B -> eta X
 9  class CLEOII_1996_I398228 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1996_I398228);
14
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      // projections
22      declare(UnstableParticles(Cuts::pid==300553),"UFS");
23      // histograms
24      book(_w_ups4,"/TMP/w_ups4");
25      book(_h,1,1,1);
26    }
27
28    void findDecay(const Particle& parent, Particles& eta) {
29      for (const Particle& p : parent.children()) {
30        if (p.pid()==PID::ETA) {
31          eta.push_back(p);
32        }
33        else if (p.abspid()==PID::PIPLUS ||
34                 p.abspid()==PID::KPLUS  ||
35                 p.pid()==PID::PI0 ||
36                 p.pid()==PID::K0S) {
37          continue;
38        }
39        else if(!p.children().empty()) {
40          findDecay(p, eta);
41        }
42      }
43    }
44
45    /// Perform the per-event analysis
46    void analyze(const Event& event) {
47      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
48      for (const Particle& p : ufs.particles()) {
49        _w_ups4->fill();
50        const LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.mom().betaVec());
51        for (const Particle& B : p.children()) {
52          if (B.abspid()!=511 && B.abspid()!=521) continue;
53          Particles eta;
54          findDecay(B, eta);
55          for (const Particle& p2 : eta) {
56            double pEta = boost.transform(p2.mom()).p3().mod();
57            _h->fill(pEta);
58          }
59        }
60      }
61    }
62
63
64    /// Normalise histograms etc., after the run
65    void finalize() {
66      // 2 B's per upsilon and in percent
67      scale(_h, 50./ *_w_ups4);
68    }
69
70    /// @}
71
72
73    /// @name Histograms
74    /// @{
75    CounterPtr _w_ups4;
76    Histo1DPtr _h;
77    /// @}
78
79
80  };
81
82
83  RIVET_DECLARE_PLUGIN(CLEOII_1996_I398228);
84
85}