Status of the Hadronic Tau Determination of V_us

Understand

We update the extraction of |V_{us}| from hadronic tau decay data in light of recent BaBar and Belle results on the branching fractions of a number of important strange decay modes.

• A range of sum rule analyses is performed, particular attention being paid to those based on "non-spectral weights", developed previously to bring the slow convergence of the relevant integrated D=2 OPE series under improved control.
• Results from the various sum rules are shown to be in good agreement with one another, but ~3 sigma below expectations based on 3-family unitarity.
• Important avenues for future study are briefly discussed.