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BESIII_2024_I2792993

$\chi_{c1,2}\to \Lambda\bar\Lambda^0\phi$ decays
Experiment: BESIII (BEPC)
Inspire ID: 2792993
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 110 (2024) 3, 032016
  • arXiv: 2405.20638
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing chi_c1 abd chi_c2, original e+e- -> psi(2S)

Measurements of mass distributions in $\chi_{c1,2}\to \Lambda\bar\Lambda^0\phi$ decays. The data were read from the plots in the paper and may not be corrected for efficiency but are background subtracted.

Source code: BESIII_2024_I2792993.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  chi_c1,2 -> Lambda Lambdabar0 phi
10  class BESIII_2024_I2792993 : public Analysis {
11  public:
12
13    /// Constructor
14    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2024_I2792993);
15
16    /// @name Analysis methods
17    /// @{
18
19    /// Book histograms and initialise projections before the run
20    void init() {
21      UnstableParticles ufs = UnstableParticles(Cuts::pid==20443 or
22						Cuts::pid==445);
23      declare(ufs, "UFS");
24      DecayedParticles chi(ufs);
25      chi.addStable( PID::PHI);
26      chi.addStable( PID::LAMBDA);
27      chi.addStable(-PID::LAMBDA);
28      declare(chi, "chi");
29      // histos
30      for(unsigned int ix=0;ix<2;++ix)
31        for(unsigned int iy=0;iy<3;++iy)
32          book(_h[ix][iy],1+ix,1,1+iy);
33
34    }
35
36
37    /// Perform the per-event analysis
38    void analyze(const Event& event) {
39      static const map<PdgId,unsigned int> & mode = { { 3122,1}, {-3122,1}, { 333,1} };
40      DecayedParticles chi = apply<DecayedParticles>(event, "chi");
41      for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
42	if(!chi.modeMatches(ix,3,mode)) continue;
43        unsigned int imode = chi.decaying()[ix].pid()==20443 ? 0 : 1;
44	const Particle & lam = chi.decayProducts()[ix].at( 3122)[0];
45	const Particle & lamb = chi.decayProducts()[ix].at(-3122)[0];
46	const Particle & phi  = chi.decayProducts()[ix].at(  333)[0];
47	_h[imode][2]->fill((lam .momentum()+lamb.momentum()).mass());
48	_h[imode][0]->fill((lam .momentum()+phi .momentum()).mass());
49	_h[imode][1]->fill((lamb.momentum()+phi .momentum()).mass());
50      }
51
52    }
53
54
55    /// Normalise histograms etc., after the run
56    void finalize() {
57      for(unsigned int ix=0;ix<2;++ix)
58        for(unsigned int iy=0;iy<3;++iy)
59          normalize(_h[ix][iy],1.,false);
60    }
61
62    /// @}
63
64    /// @name Histograms
65    /// @{
66    Histo1DPtr _h[2][3];
67    /// @}
68
69  };
70
71
72  RIVET_DECLARE_PLUGIN(BESIII_2024_I2792993);
73
74}