Search for the FCNC charmonium decay J/ψ → D0μ+μ− + c.c

Based on a data sample of (10087 ± 44) × 10 6 J / ψ events taken with the BESIII detector, we search for the flavor-changing neutral current charmonium decay J / ψ → D 0 μ + μ − + c.c. . No significant signal above the background is observed, and the upper limit on its branching fraction is set to be ℬ( J / ψ → D 0 μ + μ − + c.c.) < 1.1 × 10 − 7 at the 90% confidence level. This marks the first search for a flavor-changing neutral current charmonium decay involving muons in the final state.