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BESIII_2016_I1411448

$J/\psi\to p \bar{p}\phi$
Experiment: BESIII (BEPC)
Inspire ID: 1411448
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 93 (2016) 5, 052010
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing J/psi originally e+e-

Measurement of the mass distributions in the decay $J/\psi\to p \bar{p}\phi$. The data were read from the plots in the paper. It is also not clear that any resolution effects have been unfolded.

Source code: BESIII_2016_I1411448.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/UnstableParticles.hh"
 4#include "Rivet/Projections/DecayedParticles.hh"
 5
 6namespace Rivet {
 7
 8
 9  /// @brief J/psi -> p pbar phi
10  class BESIII_2016_I1411448 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2016_I1411448);
15
16
17    /// @name Analysis methods
18    /// @{
19
20    /// Book histograms and initialise projections before the run
21    void init() {
22      UnstableParticles ufs = UnstableParticles(Cuts::pid==443);
23      declare(ufs, "UFS");
24      DecayedParticles psi(ufs);
25      psi.addStable(PID::PI0);
26      psi.addStable(PID::K0S);
27      psi.addStable(PID::ETA);
28      psi.addStable(PID::ETAPRIME);
29      psi.addStable(PID::OMEGA);
30      psi.addStable(PID::PHI);
31      declare(psi, "psi");
32      for(unsigned int ix=0;ix<6;++ix)
33	book(_h[ix],1,1,1+ix);
34      book(_dalitz, "dalitz",50,3.5,5.,50,3.5,5.);
35    }
36
37
38    /// Perform the per-event analysis
39    void analyze(const Event& event) {
40      static const map<PdgId,unsigned int> & mode   = { { 2212,1}, {-2212,1}, { 333,1} };
41      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
42      // loop over particles
43      for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
44	if(!psi.modeMatches(ix,3,mode)) continue;
45	const Particles & phi  = psi.decayProducts()[ix].at( 333);
46	const Particles & pp   = psi.decayProducts()[ix].at( 2212);
47	const Particles & pbar = psi.decayProducts()[ix].at(-2212);
48	double mminus = (pbar[0].momentum()+phi [0].momentum()).mass2();
49	double mplus  = (pp  [0].momentum()+phi [0].momentum()).mass2();
50	double mneut  = (pp  [0].momentum()+pbar[0].momentum()).mass2();
51	_h[1]->fill(sqrt(mplus ));
52	_h[4]->fill(sqrt(mplus ));
53	_h[0]->fill(sqrt(mneut ));
54	_h[3]->fill(sqrt(mneut ));
55	_h[2]->fill(sqrt(mminus));
56	_h[5]->fill(sqrt(mminus));
57	_dalitz->fill(mplus,mminus);
58      }
59    }
60
61
62    /// Normalise histograms etc., after the run
63    void finalize() {
64      for(unsigned int ix=0;ix<6;++ix)
65	normalize(_h[ix]);
66      normalize(_dalitz);
67    }
68
69    /// @}
70
71
72    /// @name Histograms
73    /// @{
74    Histo1DPtr _h[6];
75    Histo2DPtr _dalitz;
76    /// @}
77
78
79  };
80
81
82  RIVET_DECLARE_PLUGIN(BESIII_2016_I1411448);
83
84}