Speaker
Description
We describe recent developments in the determination of the strong coupling $\alpha_s$ from finite energy sum rule (FESR) analyses of non-strange spectral distributions measured in hadronic $\tau$ decay. This includes details of an isovector, vector channel analysis employing a improved version of the relevant spectral function obtained via use of a recent BaBar determination of the $\tau\rightarrow K\bar{K} \nu_\tau$ distribution and improved CVC-based higher-multiplicity distributions obtained using recent electro-production cross-section results. We also use this improved spectral function to explore recently debated systematic issues in past FESR determinations, as well as describing new developments clarifying the understanding of what is actually learned in those determinations, and the modifications this understanding necessitates in the interpretation of those results.
