Rivet analyses referenceBESIII_2013_I1227512$\psi(2S)\to p \bar{p}\eta$Experiment: BESIII (BEPC) Inspire ID: 1227512 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $\psi(2S)\to p \bar{p}\eta$. 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_I1227512.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 eta
10 class BESIII_2013_I1227512 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2013_I1227512);
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 for(unsigned int ix=0;ix<3;++ix)
31 book(_h[ix],1,1,1+ix);
32 book(_dalitz, "dalitz",50,2.,8.,50,2.,8.);
33 }
34
35
36 /// Perform the per-event analysis
37 void analyze(const Event& event) {
38 static const map<PdgId,unsigned int> & mode = { { 2212,1}, {-2212,1}, { 221,1} };
39 DecayedParticles psi = apply<DecayedParticles>(event, "psi");
40 // loop over particles
41 for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
42 if(!psi.modeMatches(ix,3,mode)) continue;
43 const Particle & eta = psi.decayProducts()[ix].at( 221 )[0];
44 const Particle & pp = psi.decayProducts()[ix].at( 2212)[0];
45 const Particle & pbar = psi.decayProducts()[ix].at(-2212)[0];
46 double mminus = (pbar.momentum()+eta.momentum()).mass2();
47 double mplus = (pp .momentum()+eta.momentum()).mass2();
48 _h[0]->fill(sqrt(mplus));
49 _h[1]->fill(sqrt(mminus));
50 _h[2]->fill((pp.momentum()+pbar.momentum()).mass());
51 _dalitz->fill(mplus,mminus);
52 }
53 }
54
55
56 /// Normalise histograms etc., after the run
57 void finalize() {
58 normalize(_dalitz);
59 for(unsigned int ix=0;ix<3;++ix)
60 normalize(_h[ix],1.,false);
61 }
62
63 /// @}
64
65
66 /// @name Histograms
67 /// @{
68 Histo1DPtr _h[3];
69 Histo2DPtr _dalitz;
70 /// @}
71
72
73 };
74
75
76 RIVET_DECLARE_PLUGIN(BESIII_2013_I1227512);
77
78}
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