Tau Decays and ${\alpha }_s$

Abstract

The evolution of the determination of the strong coupling constant ${\alpha }_s$ from the leptonic branching ratios, the lifetime, and the invariant mass distributions of the hadronic final state of the $\tau$ lepton over the last two decades is briefly reviewed. The improvements in the latest ALEPH update are described in some detail. Currently this is one of the most precise ${\alpha }_s$ determinations. Together with the other determination at the $Z$ boson mass pole, they constitutes the most accurate test of the asymptotic freedom in QCD.

5 pages, 3 figures, proceedings for TAU 2014, published version

References in corpus (7)

• The global electroweak fit at NNLO and prospects for the LHC and ILC
• Hadronic Z- and tau-Decays in Order alpha_s^4
• The strong coupling from the revised ALEPH data for hadronic $\tau$ decays
• Alpha_s(M_Z) from hadronic tau decays
• ${\alpha }_s$ from $\tau$ decays: contour-improved versus fixed-order summation in a new QCD perturbation expansion
• Modified Contour-Improved Perturbation Theory
• On the determination of alpha_s from hadronic tau decays with contour-improved, fixed order and renormalon-chain perturbation theory