Measurement of the Cabibbo-Suppressed Decaysτ→Kντandτ→Kντ+nπ0

Abstract

The branching fractions for the Cabibbo-suppressed $\tau$ decays are measured using the DELCO detector at PEP. The results, $R(\tau \to K{\nu }_{\tau })=(0.59\mathrm{}\pm 0.18)\%$ and $R(\tau \to K{\nu }_{\tau }+n{\pi }^0)=(1.71\mathrm{}\pm 0.29)\%$ including $n=0\mathrm{}$, are in agreement with the standard theory of sequential leptons and with $\tau -\mu -e$ universality.