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BESIII_2013_I1120737

$\psi(2S)\to p \bar{p}\pi^0$
Experiment: BESIII (BEPC)
Inspire ID: 1120737
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.Lett. 110 (2013) 2, 022001
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing psi(2S) originally e+e-

Measurement of the mass distributions in the decay $\psi(2S)\to p \bar{p}\pi^0$. 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_2013_I1120737.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 psi(2S) -> p pbar pi0
10  class BESIII_2013_I1120737 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2013_I1120737);
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==100443);
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      declare(psi, "psi");
30      book(_h_ppi0,1,1,1);
31      book(_dalitz, "dalitz",50,1.,8.,50,1.,8.);
32    }
33
34
35    /// Perform the per-event analysis
36    void analyze(const Event& event) {
37      static const map<PdgId,unsigned int> & mode   = { { 2212,1}, {-2212,1}, { 111,1} };
38      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
39      // loop over particles
40      for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
41	if(!psi.modeMatches(ix,3,mode)) continue;
42	const Particles & pi0  = psi.decayProducts()[ix].at( 111);
43	const Particles & pp   = psi.decayProducts()[ix].at( 2212);
44	const Particles & pbar = psi.decayProducts()[ix].at(-2212);
45	double mminus = (pbar[0].momentum()+pi0 [0].momentum()).mass2();
46	double mplus  = (pp  [0].momentum()+pi0 [0].momentum()).mass2();
47	_h_ppi0->fill(sqrt(mplus ));
48	_dalitz->fill(mplus,mminus);
49      }
50    }
51
52
53    /// Normalise histograms etc., after the run
54    void finalize() {
55      normalize(_dalitz);
56      normalize(_h_ppi0);
57    }
58
59    /// @}
60
61
62    /// @name Histograms
63    /// @{
64    Histo1DPtr _h_ppi0;
65    Histo2DPtr _dalitz;
66    /// @}
67
68
69  };
70
71
72  RIVET_DECLARE_PLUGIN(BESIII_2013_I1120737);
73
74}