Observation of $\eta_{c}$ decay into $\Sigma^{+}\bar{\Sigma}^{-}$ and   $\Xi^{-}\bar{\Xi}^{+}$ final states
  Using a data sample of $2.25\times10^{8}$ $J/\psi$ 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 $(2.11\pm0.28_{\rm stat.}\pm0.18_{\rm syst.}\pm0.50_{\rm PDG})\times10^{-3}$ and $(0.89\pm0.16_{\rm stat.}\pm0.08_{\rm syst.}\pm0.21_{\rm PDG})\times10^{-3}$ 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. 
The BESIII Collaboration: M. Ablikim, M. N. Achasov, O. Albayrak, D.   J. Ambrose, F. F. An, Q. An, J. Z. Bai, Y. Ban, J. Be...
hep-ex