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Conference papers

Improved alpha_s from tau decays

Abstract : We present an update of the measurement of αS(m2τ) from ALEPH τ hadronic spectral functions. We report a study of the perturbative prediction(s) showing that the fixed-order perturbation theory manifests convergence problems not presented in the contour-improved calculation. Potential systematic effects from quark-hadron duality violations are estimated to be within the quoted systematic errors. The fit result is αS(m2τ) =0.344±0.005±0.007, where the first error is experimental and the second theoretical. After evolution, the αS(m2Z) determined from τ data is the most precise one to date, in agreement with the corresponding N3LO value derived from Z decays.
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Conference papers
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Contributor : Sabine Starita <>
Submitted on : Friday, March 13, 2009 - 11:12:50 AM
Last modification on : Wednesday, September 16, 2020 - 4:21:50 PM

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  • HAL Id : in2p3-00287576, version 1
  • ARXIV : 0805.2825



B. Malaescu. Improved alpha_s from tau decays. 43e Rencontres de Moriond QCD and High Energy Interactions, Mar 2008, La Thuile, Italy. pp.147-150. ⟨in2p3-00287576⟩



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