Tau decay events involving [eta] mesons

Abstract

The characteristics of tau decays to final states involving [eta] mesons are presented. The data sample, which corresponds to an integrated luminosity of 300pb-1, was taken at the PEP e+e- colliding beam facility using the High Resolution Spectrometer. The storage ring was operated at [radical sign]s = 29 GeV. The [eta] production appears to be only compatible with the decay , which violates isospin and G-parity conservation. This decay, thus, proceeds via a second-class vector current. The branching ratio (5.1 +/- 1.5)% explains much of the current discrepancy between the one-prong topological branching ratio and the sum of the individual one-prong modes.