Search for lepton flavor violating τ− decays into ℓ−η, ℓ−η′ and ℓ−π0

We have searched for lepton-flavor-violating τ decays with a pseudoscalar meson (η, η′ and π0) using a data sample of 401 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. No evidence for these decays is found and we set the following upper limits on the branching fractions: B(τ−→e−η)<9.2×10−8, B(τ−→μ−η)<6.5×10−8, B(τ−→e−η′)<1.6×10−7, B(τ−→μ−η′)<1.3×10−7, B(τ−→e−π0)<8.0×10−8 and B(τ−→μ−π0)<1.2×10−7 at the 90% confidence level. These results improve our previously published upper limits by factors from 2.3 to 6.3.