First observation of the ${\eta }_c\to {\Xi }^0{\bar{\Xi }}^0$ decay

BESIII Collaboration, M. Ablikim, M. N. Achasov +761

Using $(10087\pm 44)\times 10^6$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, we report the first observation of the decay ${\eta }_c\to {\Xi }^0{\bar{\Xi }}^0$. T…