Study of $J/psi$ and $psi(3686)$ decay to $Lambdabar{Lambda}$ and $Sigma^0bar{Sigma}^0$ final states

Using $1310.6times10^6$ $J/psi$ and $447.9times10^6$ $psi(3686)$ events collected with the BESIII detector at the BEPCII $e^{+}e^{-}$ collider, the branching fractions and the angular distributions of $J/psi$ and $psi(3686)$ decays to $Lambdabar{Lambda}$ and $Sigma^0bar{Sigma}^0$ final states are measured. The branching fractions are in agreement with, and much more precise than, the averages of previously published results. The polar angular distributions of $psi(3686)$ decays are measured for the first time, while those of $J/psi$ decays are measured with much improved precision. In addition, the ratios of branching fractions $frac{mathcal{B}(psi(3686)toLambdabar{Lambda})}{mathcal{B}(J/psitoLambdabar{Lambda})}$ and $frac{mathcal{B}(psi(3686)toSigma^0bar{Sigma}^0)}{mathcal{B}(J/psitoSigma^0bar{Sigma}^0)}$ are determined to test the 12% rule.