The τ→ν τηπ process in and beyond QCD

Abstract

We estimate various sources of the τ→ν τηπ process by using QCD-duality sum rule information on the decay constants of standard and exotic mesons. We use the π→ l ν l decay in order to constrain the effects of new interactions. We conclude from our analysis that in al cases, the τ→ν τηπ branching ration is small. We also point out that the present data on the τ→νπ process already provide an upper limit of 0.1% on the ηπ mode while the τ→ν τKK̄ data imply an upper limit of 0.5% if the a 0 (980)- meson is a four-quark state.