Search for lepton-flavor-violating τ→ℓV0τ→ℓV0 decays at Belle

We have searched for neutrinoless τ lepton decays into ℓ   and V0V0, where ℓ   stands for an electron or muon, and V0V0 for a vector meson (ϕ, ω  , K∗0K∗0, K¯∗0 or ρ0ρ0), using 543 fb−1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e−e+e− collider. No excess of signal events over the expected background has been observed, and we set upper limits on the branching fractions in the range (5.9–18)×10−8(5.9–18)×10−8 at the 90% confidence level. These upper limits are significantly more restrictive than our previous results for the ℓϕ  , ℓK∗0ℓK∗0, ℓK¯∗0 and ℓρ0ℓρ0 modes.