Rare τ decays inR-parity violating supersymmetry

We constrain, from rare τ decays, several combinations of λ- and λ'-type couplings coming from supersymmetry without R -parity. The processes that we consider are τ → ℓ M , τ → ℓ i ℓ j ℓ k and τ → ℓγ, where ℓ stands for either e or μ, and M is the generic symbol for a meson. We update several existing bounds, and provide a few new ones too.