Search for the charmonium weak decay J/ψ → D̄⁰K̄⁰+c.c.

A bstract Based on a sample of (10087 ± 44) × 10 6 J / ψ events collected at the center-of-mass energy √s=3.0969 s = 3.0969 GeV with the BESIII detector, we search for the charmonium rare weak decay J/ψ → D̄⁰K̄⁰+c.c. J / ψ → D ¯ 0 K ¯ ∗ 0 + c . c . . No significant signal is observed, and the upper limit on its decay branching fraction at the 90% confidence level is set as 1.4 × 10 − 7 , improving the sensitivity of the previous best limit by an order of magnitude.