Strange Hadronic Tau Data 1

We report on recent work to determine the CKM matrix element |Vus| using strange hadronic τ decay data. We use the recent OPAL update of the strange spectral function, while on the theory side we update the dimension-two perturbative contribution including the recently calculated α 3 s terms. Our result |Vus| = 0.2220±0.0033 is already competitive with the standard extraction from Ke3 decays and other new proposals to determine |Vus|. The actual uncertainty on |Vus| from τ data is dominated largely by experiment and will eventually be much reduced by B-factories and future τ -charm factory data, providing one of the most accurate determinations of this Standard Model parameter. October 2006 Invited talk given by J.P. at “ICHEP’06, 26-July to 2-August 2006, Moscow, Russia”.