α <inf>s</inf> from τ decays revisited

D. R. Boito, O. Catà, M. Golterman, M. Jamin, K. Maltman, J. Osborne, S. Peris

Research output: Contribution to journalArticleResearchpeer-review


Being a determination at low energies, the analysis of hadronic τ decay data provides a rather precise determination of the strong coupling α s after evolving the result to M Z. At such a level of precision, even small non-perturbative effects become relevant for the central value and error. While those effects had been taken into account in the framework of the operator product expansion, contributions going beyond it, so-called duality violations, have previously been neglected. The following investigation fills this gap through a finite-energy sum rule analysis of τ decay spectra from the OPAL experiment, including duality violations and performing a consistent fit of all appearing QCD parameters. The resulting values for α s(M τ) are 0.307(19) in fixed-order perturbation theory and 0.322(26) in contour-improved perturbation theory, which translates to the n f=5 values 0.1169(25) and 0.1187(32) at M Z, respectively. © 2012 Elsevier B.V..
Original languageEnglish
Pages (from-to)157-160
JournalNuclear Physics B - Proceedings Supplements
Publication statusPublished - 1 Apr 2012


  • α s
  • τ decay
  • Duality violation


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