Based on a sample of $(10087\pm44)\times10^6$ $J/\psi$ events collected at the center-of-mass energy $\sqrt{ s}$ = 3.0969 GeV with the BESIII detector, we search for the charmonium rare weak decay $J/\psi\to\bar{ D}^0\bar{ K}^{ *0}+{ \rm c.c.}$. No significant signal is observed, and the upper limit on its decay branching fraction at the 90% confidence level is set as $1.9\times10^{ -7}$, improving the sensitivity of the previous best limit by an order of magnitude.
Categories: hep-ex