Search for the lepton flavor violation processes J/ψ→ μτ and eτ

The lepton flavor violation processes J / ψ → μ τ and eτ are searched for using a sample of 5.8 × 10 7 J / ψ events collected with the BESII detector. Zero and one candidate events, consistent with the estimated background, are observed in J / ψ → μ τ , τ → e ν ¯ e ν τ and J / ψ → e τ , τ → μ ν ¯ μ ν τ decays, respectively. Upper limits on the branching ratios are determined to be Br ( J / ψ → μ τ ) 2.0 × 10 − 6 and Br ( J / ψ → e τ ) 8.3 × 10 − 6 at the 90% confidence level (C.L.).