Rivet analyses referenceBESIII_2013_I1120737$\psi(2S)\to p \bar{p}\pi^0$Experiment: BESIII (BEPC) Inspire ID: 1120737 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
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}
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