Formula omitted] from the (revised) ALEPH data for τ decay

Abstract

We present a new analysis of αs from hadronic τ decays based on the recently revised ALEPH data, employing a strategy previously applied to the OPAL data. We examine critically the approach traditionally used, comparing it to our strategy, and commenting on the main differences between the two. Our analysis yields the values αs(mτ2)=0.296±0.010 using fixed-order perturbation theory, and αs(mτ2)=0.310±0.014 using contour-improved perturbation theory. Averaging these values with our previously obtained values from the OPAL data, we find αs(mτ2)=0.303±0.009, respectively, αs(mτ2)=0.319±0.012, as the most reliable results for αs from τ decays currently available.