Precise measurement of hadronic $\tau$-decays in modes with $\eta$ mesons

Abstract

We have measured branching fractions of hadronic $\tau$ decays involving an $\eta$ meson using 485 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We obtain the following branching fractions: $\mathcal{B}({\tau }^{-}\to K^{-}\eta {\nu }_{\tau })=(1.62\pm 0.05\pm 0.09)\times 10^{-4}$, $\mathcal{B}({\tau }^{-}\to K^{-}{\pi }^0\eta {\nu }_{\tau })=(4.7\pm 1.1\pm 0.4)\times 10^{-5}$, $\mathcal{B}({\tau }^{-}\to {\pi }^{-}{\pi }^0\eta {\nu }_{\tau })=(1.39\pm 0.03\pm 0.07)\times 10^{-3}$, and $\mathcal{B}({\tau }^{-}\to K^{\ast -}\eta {\nu }_{\tau })=(1.13\pm 0.19\pm 0.07)\times 10^{-4}$ improving the accuracy compared to the best previous measurements by factors of six, eight, four and four, respectively.

BELLE-CONF-0714; contributed to EPS 2007 and Lepton Photon 2007