Study of the $J/ψ\to Λ\barΣ^0η$ reaction

We study the isospin violating $J/ψ\to Λ\bar Σ^0 η$ reaction, recently measured by the BESIII collaboration, by looking at the dominant terms with $\bar Σ^0$ and a pair of pseudoscalar-baryon particles that form together an SU(3) singlet and can thus couple to the $J/ψ$. Next we allow these pairs to undergo final state interaction to produce the final $ηΛ$. We find that the relevant original channels are $\bar K N$ and $K Ξ$, and the non cancelation of terms involving charged and neutral particles, because of their different masses, is responsible for the reaction. With that mechanism we find a good agreement with the three experimental mass distributions.