Rivet analyses referenceBESIII_2019_I1712729$J/\psi\to \phi\eta\eta^\prime$Experiment: BESIII (BEPC) Inspire ID: 1712729 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $J/\psi\to \phi\eta\eta^\prime$. 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_2019_I1712729.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 -> phi eta eta'
10 class BESIII_2019_I1712729 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2019_I1712729);
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<2;++ix)
33 book(_h[ix],1,1,1+ix);
34 book(_dalitz, "dalitz",50,3.5,7.,50,2.0,5.);
35 }
36
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { 333,1}, { 221,1}, { 331,1} };
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 Particle & phi = psi.decayProducts()[ix].at( 333)[0];
46 const Particle & eta = psi.decayProducts()[ix].at( 221)[0];
47 const Particle & etap = psi.decayProducts()[ix].at( 331)[0];
48 double mphieta = (phi.momentum()+eta .momentum()).mass2();
49 double mphietap = (phi.momentum()+etap.momentum()).mass2();
50 _h[0]->fill(sqrt(mphietap));
51 _h[1]->fill(sqrt(mphietap));
52 _dalitz->fill(mphietap,mphieta);
53 }
54 }
55
56
57 /// Normalise histograms etc., after the run
58 void finalize() {
59 for(unsigned int ix=0;ix<2;++ix)
60 normalize(_h[ix]);
61 normalize(_dalitz);
62 }
63
64 /// @}
65
66
67 /// @name Histograms
68 /// @{
69 Histo1DPtr _h[2];
70 Histo2DPtr _dalitz;
71 /// @}
72
73
74 };
75
76
77 RIVET_DECLARE_PLUGIN(BESIII_2019_I1712729);
78
79}
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