First measurements of the branching fractions of $J/\psi$ and $\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\eta$

Abstract

Based on $(10087\pm 44)\times 10^6$ $J/\psi$ and $(2712\pm 14)\times 10^6$ $\psi (3686)$ events collected with the BESIII detector at the BEPCII collider, the hadronic decays $J/\psi \to {\Sigma }^0{\bar{\Sigma }}^0\eta$ and $\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\eta$ are observed for the first time. The corresponding branching fractions are measured to be $\mathcal{B}(J/\psi \to {\Sigma }^0{\bar{\Sigma }}^0\eta )=(7.5\pm 0.3\pm 0.8)\times 10^{-5}$ and $\mathcal{B}(\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\eta )=(1.3\pm 0.1\pm 0.1)\times 10^{-5}$, respectively, where the first uncertainties are statistical, and the second systematic. The ratio $\text{Q}\approx \frac{\mathcal{B}(\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\eta )}{\mathcal{B}(J/\psi \to {\Sigma }^0{\bar{\Sigma }}^0\eta )}$ is determined to be $(17.3\pm 1.5\pm 1.7)\%$, which is con sistent with the 12\%-rule within 3.0$\sigma$.~No significant intermediate states or threshold enhancements are observed in the ${\Sigma }^0$(${\bar{\Sigma }}^0$)$\eta$ and ${\Sigma }^0$${\bar{\Sigma }}^0$ invariant mass spectra.