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CLEO_1985_I218314

Momentum spectrum of $\phi$ mesons in $B$ decays
Experiment: CLEO (CESR)
Inspire ID: 218314
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.Lett. 56 (1986) 800
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing Upslion(4S), originaly e+e-

Momentum spectrum of $\phi$ mesons in $B$ meson decays, where the $B$ mesons are produced at the $\Upsilon(4S)$

Source code: CLEO_1985_I218314.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4
 5namespace Rivet {
 6
 7
 8  /// @brief B -> phi X
 9  class CLEO_1985_I218314 : public Analysis {
10  public:
11
12    /// Constructor
13    RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_1985_I218314);
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(_h,4,1,1);
25      book(_c,"TMP/nB");
26    }
27
28    void findDecay(const Particle& parent, Particles& phi) {
29      for (const Particle& p : parent.children()) {
30        if (p.abspid()==333) {
31          phi.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        else if (!p.children().empty()) {
39          findDecay(p,phi);
40        }
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        const LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.mom().betaVec());
50        for (const Particle& B:p.children()) {
51          if (B.abspid()!=511 && B.abspid()!=521) continue;
52          _c->fill();
53          Particles phi;
54          findDecay(B,phi);
55          for (const Particle & p2 : phi) {
56            const double pmod = boost.transform(p2.mom()).p3().mod();
57            _h->fill(pmod);
58          }
59        }
60      }
61    }
62
63
64    /// Normalise histograms etc., after the run
65    void finalize() {
66      scale(_h,1./ *_c);
67    }
68
69    /// @}
70
71
72    /// @name Histograms
73    /// @{
74    Histo1DPtr _h;
75    CounterPtr _c;
76    /// @}
77
78
79  };
80
81
82  RIVET_DECLARE_PLUGIN(CLEO_1985_I218314);
83
84}