Hadronic Tau Decays : Anomalies and Resolution

Hadronic tau decays offer clean environment for the precise determinations of parameters of the Standard Model (SM). The fundamental quantities like CKM elements Vus and strange quark mass can be calculated from the study of spectral functions based observables. In this talk we discuss two of the long-standing issues related to hadronic tau decays. One is the ∼ 3 σ disagreement of Vus value extracted from inclusive tau decays, with values obtained from semileptonic kaon decay as well as from CKM unitarity. The other issue is the CP asymmetry in exclusive τ ∼ K π ν. The experimental value for the CP asymmetry is also in ∼ 3 σ disagreement with the SM. We review both observables in the SM and propose a common solution to both of anomalies via a nonstandard tensor interaction.