Search for the rare decay J/ψ → γ D⁰+c.c. at BESIII

Using (10087±44)×10⁶J/ψ events collected with the BESIII detector, we search for the rare decay J/ψ → γ D⁰+c.c. for the first time. No obvious signal is observed and the upper limit on the branching fraction is determined to be B(J/ψ → γ D⁰+c.c.)< 9.1 × 10⁻⁸ at 90% confidence level.