Observation of $eta_{c}$ decay into $Sigma^{+}bar{Sigma}^{-}$ and $Xi^{-}bar{Xi}^{+}$ final states

Using a data sample of $2.25times10^{8}$ $J/psi$ events collected with the BESIII detector, we present the first observation of the decays of $eta_{c}$ mesons to $Sigma^{+}bar{Sigma}^{-}$ and $Xi^{-}bar{Xi}^{+}$. The branching fractions are measured to be $(2.11pm0.28_{rm stat.}pm0.18_{rm syst.}pm0.50_{rm PDG})times10^{-3}$ and $(0.89pm0.16_{rm stat.}pm0.08_{rm syst.}pm0.21_{rm PDG})times10^{-3}$ for $eta_{c} to Sigma^{+}bar{Sigma}^{-}$ and $Xi^{-}bar{Xi}^{+}$, respectively. These branching fractions provide important information on the helicity selection rule in charmonium-decay processes.