Updated determination of [formula omitted] from hadronic τ decays

Abstract

Recently we introduced a new framework to extract αs from the non-strange hadronic τ-decay spectral functions taking into account duality violations and treating nonperturbative effects self-consistently. Using an updated version of the OPAL 1998 data, we obtain αsFO(mτ2)=0.325±0.018 and αsCl(mτ2)=0.347±0.025 in fixed-order and contour-improved perturbation theory, respectively. The results from our multi-parameter nonlinear fits were corroborated by a Markov-Chain Monte Carlo investigation of the posterior probability distributions of the model parameters.