Extraction of ms and |Vus | from Hadronic Tau Decays 1

We review recent work to determine the strange quark mass ms as well as the proposal to determine |Vus| using hadronic τ decay data. The recent update of the strange spectral function by OPAL and their moments of the invariant mass distribution are employed. Our results are |Vus| = 0.2208± 0.0034 and ms(2GeV) = 81±22 MeV. Our result is already competitive to the standard extraction of |Vus| from Ke3 decays and to the new proposals to determine it. The error on |Vus| is dominated by experiment and will be eventually much improved by the B-factories hadronic τ data. Ultimately, a simultaneous fit of both ms and |Vus| to a set of moments of the hadronic τ decays invariant mass distribution will provide one of the most accurate determinations of these Standard Model parameters. November 2004 Invited talk given by J.P. at “ TAU04, 14-17 September 2004, Nara, Japan”.