Rivet analyses

J/ψ and ψ(2S) decays to ηΣ⁺Σ̄⁻

Experiment: BESIII (BEPC)

Inspire ID: 2166759

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 210.09601

Beams: * *

Beam energies: ANY

Run details: - Any process producing J/psi or psi(2S), originally e+e-

Measurements of mass distributions in J/ψ and ψ(2S) decays to ηΣ⁺Σ̄⁻. 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`

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/DecayedParticles.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief J/.psi anbd psi(2S) -> eta Sigma+ Sigmabar-
  class BESIII_2022_I2166759 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2166759);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::pid == 443 or Cuts::pid == 100443);
      declare(ufs, "UFS");
      DecayedParticles psi(ufs);
      psi.addStable(PID::ETA);
      psi.addStable(PID::SIGMAPLUS);
      psi.addStable(PID::SIGMAMINUS);
      psi.addStable(-PID::SIGMAPLUS);
      psi.addStable(-PID::SIGMAMINUS);
      declare(psi, "psi");
      // histos
      for (unsigned int ix = 0; ix < 6; ++ix) book(_h[ix], 1, 1, 1 + ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{3222, 1}, {-3222, 1}, {221, 1}};
      DecayedParticles psi = apply<DecayedParticles>(event, "psi");
      for (unsigned int ix = 0; ix < psi.decaying().size(); ++ix) {
        if (!psi.modeMatches(ix, 3, mode)) continue;
        unsigned int ioff = psi.decaying()[ix].pid() == 443 ? 0 : 3;
        const Particle& sigp = psi.decayProducts()[ix].at(3222)[0];
        const Particle& sigm = psi.decayProducts()[ix].at(-3222)[0];
        const Particle& eta = psi.decayProducts()[ix].at(221)[0];
        _h[ioff + 0]->fill((sigp.momentum() + eta.momentum()).mass());
        _h[ioff + 1]->fill((sigm.momentum() + eta.momentum()).mass());
        _h[ioff + 2]->fill((sigp.momentum() + sigm.momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 6; ++ix) normalize(_h[ix], 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[6];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BESIII_2022_I2166759);

}

Rivet analyses

J/ψ and ψ(2S) decays to ηΣ+Σ̄−

Source code:BESIII_2022_I2166759.cc

J/ψ and ψ(2S) decays to ηΣ⁺Σ̄⁻

Source code:`BESIII_2022_I2166759.cc`