10-17 July 2019
Europe/Brussels timezone

The strong coupling from e+e- to hadrons

12 Jul 2019, 16:30
Campus Ledeganck - Aud. 6 (Ghent)

Campus Ledeganck - Aud. 6


Parallel talk QCD and Hadronic Physics QCD and Hadronic Physics


Diogo Boito (Universidade de São Paulo)


We determine the strong coupling, $\alpha_s$, using finite-energy sum
rules and a new compilation of the hadronic $R$-ratio from available
data for $e^+e^- \to {\rm hadrons}$ below the charm threshold. Quoting our
final results at the tau mass to facilitate comparison to the results
of analyses of hadronic tau decay data, we find
$\alpha_s(m_\tau^2) = 0.298 \pm 0.017$ in fixed-order perturbation theory
and $\alpha_s(m_\tau^2) = 0.304 \pm 0.019$ in contour-improved
perturbation theory, where the quoted errors are largely dominated by
statistics. At the $Z$ boson mass, we find $\alpha_s(m_Z^2) = 0.1158 \pm 0.0022$
and $\alpha_s(m_Z^2) = 0.1166 \pm 0.025$, respectively. Our results are
in agreement with the world average and with recent extractions from
tau decay data. Our method provides an independent and competitive
strategy for the extraction of the strong coupling below the charm

Primary authors

Diogo Boito (Universidade de São Paulo) Maarten Golterman (San Francisco State University) Alexander Keshavarzi Kim Maltman (York University) Daisuke Nomura Thomas Teubner (University of Liverpool) santiago peris (Univ. Autonoma de Barcelona)

Presentation Materials