The strong coupling from tau decays without prejudice

TL;DR

This paper reviews recent determinations of the strong coupling constant _s from tau decay data, providing updated values that surpass previous measurements in precision and reliability.

Contribution

It presents a comprehensive analysis of _s from OPAL tau decay data, comparing fixed-order and contour-improved perturbation theory methods, establishing more accurate values.

Findings

_s(m^2_ au) = 0.325 b1 0.018 (fixed-order)

_s(m^2_ au) = 0.347 b1 0.025 (contour-improved)

These results outperform earlier determinations from ALEPH and other data.

Abstract

We review our recent determination of the strong coupling \alpha_s from the OPAL data for non-strange hadronic tau decays. We find that \alpha_s(m^2_\tau) =0.325+-0.018 using fixed-order perturbation theory, and \alpha_s(m^2_\tau)=0.347+-0.025 using contour-improved perturbation theory. At present, these values supersede any earlier determinations of the strong coupling from hadronic tau decays, including those from ALEPH data.