Determination of ${\alpha }_s(M_{\tau }^2)$: a conformal mapping approach

Abstract

We discuss a new class of expansions in perturbative QCD, based on the technique of conformal mappings of the Borel plane, and apply them for the determination of ${\alpha }_s$ from the hadronic decays of the $\tau$ lepton. Using the expansion up to fifth order in the $\overline{\mathrm{MS}}$ scheme, the method leads to the prediction ${\alpha }_s(M_{\tau }^2)=0.320\pm 0.011$.

Comments: 6 pages, 2 figures. Talk given at the 11th International Workshop on Tau Lepton Physics, Manchester, UK, 13-17 September 2010