A new determination of \alpha_s from hadronic \tau\ decays
Abstract
We present a new framework for the extraction of the strong coupling from hadronic \tau decays through finite-energy sum rules. Our focus is on the small, but still significant non-perturbative effects that, in principle, affect both the central value and the systematic error. We employ a quantitative model in order to accommodate violations of quark-hadron duality, and enforce a consistent treatment of the higher-dimensional contributions of the Operator Product Expansion to our sum rules. Using 1998 OPAL data for the non-strange isovector vector and axial-vector spectral functions, we find the n_f=3 values \alpha_s(m_\tau^2)=0.307+-0.019 in fixed-order perturbation theory, and 0.322+-0.026 in contour-improved perturbation theory. For comparison, the original OPAL analysis of the same data led to the values 0.324+-0.014 (fixed-order) and 0.348+-0.021 (contour-improved).
Keywords
Cite
@article{arxiv.1110.1127,
title = {A new determination of \alpha_s from hadronic \tau\ decays},
author = {Diogo Boito and Oscar Cata and Maarten Golterman and Matthias Jamin and Kim Maltman and James Osborne and Santiago Peris},
journal= {arXiv preprint arXiv:1110.1127},
year = {2013}
}
Comments
31 pages, 7 figures, revtex, version accepted for publication, minor changes, reference added