Study of SU(2) and SU(3) violations in Jψ baryonic decays

We present a systematic study of SU(3) symmetry breaking in Jψ baryonic decays; first measurements are given for the forbidden processes Jψ → Ξ− (1530) Ξ+ + c.c. and Ξ0 (1530) Ξ0 + c.c. Branching ratios for Jgy → 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: Jψ → Ξ−Ξ+, Σ±(1385)Σ∓(1385). In addition, upper limits are determined on purely electromagnetic transitions Jψ → Σ(1385)Λ + c.c. and Jψ → Δ+p + c.c., both involving SU(2) and SU(3) breaking. The first observation of the isospin forbidden decay Jψ → ΛΛπ0 is also presented.