K0 production in one prong tau decays

CERN-LEP. From a sample of about 75000 $\tau$ decays identified with the ALEPH detector, $K^0$ production in 1-prong hadronic decays is investigated by tagging the $K^0_L$ component in a hadronic calorimeter. Results are given for the final states $\nu_{\tau}h^-K^0$ and $\nu_{\tau}h^-\pi^0K^0$ where the $h^-$ is separated into $\pi$ and $K$ contributions by means of the $dE/dx$ measurement in the central detector. The resulting branching ratios are: $$\begin{eqnarray} (B\tau\to\nu_{\tau}\pi^-K^0) = (0.88\pm0.14\pm0.09)\%,\\ (B\tau\to\nu_{\tau}K^-K^0) = (0.29\pm0.12\pm0.03)\%,\\ (B\tau\to\nu_{\tau}\pi^-\pi^0K^0) = (0.33\pm0.14\pm0.07)\%\\ \mathrm{and}\quad (B\tau\to\nu_{\tau}K^-\pi^0K^0) = (0.05\pm0.05\pm0.01)\%. \end{eqnarray}$$. The $K^*$ decay rate in the $K^0\pi$ channel agrees with that in the $K\pi^0$ mode: the combined value for the branching ratio is $(B\tau\to\nu_{\tau}K^{*^-}) = (1.45\pm0.13\pm0.11)\%$.