Rivet analyses referenceBESIII_2022_I2166759$J/\psi$ and $\psi(2S)$ decays to $\eta\Sigma^+\bar\Sigma^-$Experiment: BESIII (BEPC) Inspire ID: 2166759 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurements of mass distributions in $J/\psi$ and $\psi(2S)$ decays to $\eta\Sigma^+\bar\Sigma^-$. The data were read from the plots in the paper and may not be corrected for efficiency but the background given in the paper has been subtracted. Source code: BESIII_2022_I2166759.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 anbd psi(2S) -> eta Sigma+ Sigmabar-
10 class BESIII_2022_I2166759 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2166759);
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 or
23 Cuts::pid==100443);
24 declare(ufs, "UFS");
25 DecayedParticles psi(ufs);
26 psi.addStable( PID::ETA);
27 psi.addStable( PID::SIGMAPLUS);
28 psi.addStable( PID::SIGMAMINUS);
29 psi.addStable(-PID::SIGMAPLUS);
30 psi.addStable(-PID::SIGMAMINUS);
31 declare(psi, "psi");
32 // histos
33 for(unsigned int ix=0;ix<6;++ix)
34 book(_h[ix],1,1,1+ix);
35 }
36
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { 3222,1}, {-3222,1}, { 221,1} };
41 DecayedParticles psi = apply<DecayedParticles>(event, "psi");
42 for(unsigned int ix=0;ix<psi.decaying().size();++ix) {
43 if(!psi.modeMatches(ix,3,mode)) continue;
44 unsigned int ioff = psi.decaying()[ix].pid()==443 ? 0 : 3;
45 const Particle & sigp = psi.decayProducts()[ix].at( 3222)[0];
46 const Particle & sigm = psi.decayProducts()[ix].at(-3222)[0];
47 const Particle & eta = psi.decayProducts()[ix].at( 221)[0];
48 _h[ioff+0]->fill((sigp.momentum()+eta .momentum()).mass());
49 _h[ioff+1]->fill((sigm.momentum()+eta .momentum()).mass());
50 _h[ioff+2]->fill((sigp.momentum()+sigm.momentum()).mass());
51 }
52 }
53
54
55 /// Normalise histograms etc., after the run
56 void finalize() {
57 for(unsigned int ix=0;ix<6;++ix)
58 normalize(_h[ix],1.,false);
59 }
60
61 /// @}
62
63
64 /// @name Histograms
65 /// @{
66 Histo1DPtr _h[6];
67 /// @}
68
69
70 };
71
72
73 RIVET_DECLARE_PLUGIN(BESIII_2022_I2166759);
74
75}
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