Updated determination of ${\alpha }_s(m_{\tau }^2)$ from tau decays

Abstract

Using the most recent release of the ALEPH $\tau$ decay data, we present a very detailed phenomenological update of the ${\alpha }_s(m_{\tau }^2)$ determination. We have exploited the sensitivity to the strong coupling in many different ways, exploring several complementary methodologies. All determinations turn out to be in excellent agreement, allowing us to extract a very reliable value of the strong coupling. We find ${\alpha }_s^{(n_f=3)}(m_{\tau }^2)=0.328\pm 0.012$ which implies ${\alpha }_s^{(n_f=5)}(M_Z^2)=0.1197\pm 0.0014$. We critically revise previous work, and point out the problems flawing some recent analyses which claim slightly smaller values.

Invited contribution to the MITP workshop on Determination of the Fundamental Parameters in QCD (Mainz, 7-11 March 2016). 15 pages, 8 figures

References in corpus (1)

• Hadronic Z- and tau-Decays in Order alpha_s^4

Cited by in corpus (5)

• Precision physics with inclusive QCD processes
• Violations of Quark-Hadron Duality in Low-Energy Determinations of ${\alpha }_s$
• Borel-Laplace Sum Rules with $\tau$ decay data, using OPE with improved anomalous dimensions
• Using improved Operator Product Expansion in Borel-Laplace Sum Rules with ALEPH $\tau$ decay data, and determination of pQCD coupling
• QCD condensates and ${\alpha }_s$ from $\tau$-decay