Search for lepton-flavor-violating decays D⁰ → X⁰e±μ∓

We present a search for seven lepton-flavor-violating neutral charm meson decays of the type D⁰ → X⁰e±μ∓, where X⁰ represents a π⁰, K⁰_S, K*⁰, ρ⁰, ϕ, ω, or η meson. The analysis is based on 468  fb⁻¹ of e⁺e⁻ annihilation data collected at or close to the Υ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signals are observed, and we establish 90% confidence level upper limits on the branching fractions in the range (5.0−22.5) × 10⁻⁷. The limits are between 1 and 2 orders of magnitude more stringent than previous measurements.