ar X iv : h ep - p h / 99 02 21 7 v 1 1 F eb 1 99 9 Padé - Improved Extraction of α s ( M τ
نویسندگان
چکیده
The perturbative series used to extract α s (M τ) from the τ hadronic width exhibits slow convergence. Asymptotic Padé-approximant and Padé summation techniques provide an estimate of these unknown higher-order effects, leading to values for α s (M τ) that are about 10% smaller than current estimates. Such a reduction improves the agreement of α s (M τ) with the QCD evolution of the strong coupling constant from α s (M z).
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