Electroweak radiative corrections to semileptonic $\tau$ decays

Abstract

I present an update on the electroweak radiative correction factor to semileptonic $\tau$ decays, including a next-to-leading order resummation of large logarithms. My result differs both qualitatively and quantitatively from the one recently obtained by Davier~\etal. As two consequences, (i) the discrepancy between the predictions for the muon $g-2$ based on $\tau$ decay data and $e^+ e^-$ annihilation data increases, and (ii) the $g-2$ prediction based on $\tau$ decay data appears to be consistent (within about one standard deviation) with the experimental result from BNL.