Study of SU(2) and SU(3) Violations in $J/\psi$ Baryonic Decays

Abstract We present a systematic study of SU(3) symmetry breaking in J ψ baryonic decays; first measurements are given for the forbidden processes J ψ → Ξ − (1530) Ξ + + c.c. and Ξ 0 (1530) Ξ 0 + c.c. Branching ratios for J gy → Σ ± (1385) Σ ∓ + c.c. are also obtained; they are consistent with published values and are given with better accuracy. All these decays are only 3 times weaker than SU(3) allowed decay modes: J ψ → Ξ − Ξ + , Σ ± (1385) Σ ∓ (1385) . In addition, upper limits are determined on purely electromagnetic transitions J ψ → Σ(1385) Λ + c.c. and J ψ → Δ + p + c.c. , both involving SU(2) and SU(3) breaking. The first observation of the isospin forbidden decay J ψ → Λ Λ π 0 is also presented.