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/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.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`