The Determination of alpha_s from Tau Decays Revisited

Abstract

We revisit the determination of alpha_s(m_tau) using a fit to inclusive tau hadronic spectral moments in light of (1) the recent calculation of the fourth-order perturbative coefficient K_4 in the expansion of the Adler function, (2) new precision measurements from BABAR of e+e- annihilation cross sections, which decrease the uncertainty in the separation of vector and axial-vector spectral functions, and (3) improved results from BABAR and Belle on tau branching fractions involving kaons. We estimate that the fourth-order perturbative prediction reduces the theoretical uncertainty, introduced by the truncation of the series, by 20% with respect to earlier determinations. We discuss to some detail the perturbative prediction and show that the effect of the incomplete knowledge of the series is reduced by using the so-called contour-improved calculation, as opposed to fixed-order perturbation theory which manifests convergence problems. The corresponding theoretical uncertainties are studied at the tau and Z mass scales. Nonperturbative contributions extracted from the most inclusive fit are small, in agreement with earlier determinations. Systematic effects from quark-hadron duality violation are estimated with simple models and found to be within the quoted systematic errors. The fit gives alpha_s(m_tau) = 0.344 +- 0.005 +- 0.007, where the first error is experimental and the second theoretical. After evolution to M_Z we obtain alpha_s(M_Z) = 0.1212 +- 0.0005 +- 0.0008 +- 0.0005, where the errors are respectively experimental, theoretical and due to the evolution. The result is in agreement with the corresponding NNNLO value derived from essentially the Z width in the global electroweak fit. The alpha_s(M_Z) determination from tau decays is the most precise one to date.

arXiv comment22 pages, 7 figures

References in corpus (34)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• The four-loop beta-function in Quantum Chromodynamics
• Decoupling Relations to O(alpha_s^3) and their Connection to Low-Energy Theorems
• Strong Coupling Constant with Flavour Thresholds at Four Loops in the MS-bar Scheme
• Branching ratios and spectral functions of tau decays: final ALEPH measurements and physics implications
• Naive nonabelianization and resummation of fermion bubble chains
• The Physics of Hadronic Tau Decays
• Confronting Spectral Functions from e+e- Annihilation and tau Decays: Consequences for the Muon Magnetic Moment
• Resummation of $({\beta }_0{\alpha }_s{)}^n$ Corrections in QCD: Techniques and Applications to the $\tau$ Hadronic Width and the Heavy Quark Pole Mass
• Estimates of the higher-order QCD corrections to R(s), R_τ and deep-inelasstic scattering sum rules
• Renormalization group analysis of the tau-lepton decay within QCD
• Experimental Tests of Asymptotic Freedom
• Study of tau- -> K_S pi- nu_tau decay at Belle
• Hadronic Structure in the Decay ${\tau }^{-}\to {\nu }_{\tau }{\pi }^{-}{\pi }^0{\pi }^0$ and the Sign of the Tau Neutrino Helicity
• Duality violations and spectral sum rules
• First determination of the strong coupling constant using NNLO predictions for hadronic event shapes in e^+e^- annihilations
• Study of tau decays involving kaons, spectral functions and determination of the strange quark mass
• Accurate Determinations of ${\alpha }_s$ from Realistic Lattice QCD
• Exclusive branching fraction measurements of semileptonic tau decays into three charged hadrons, ${\tau }^{-}\to \varphi {\pi }^{-}{\nu }_{\tau }$ and ${\tau }^{-}\to \varphi K^{-}{\nu }_{\tau }$
• ${\alpha }_s(m_Z)$ from tau decays with matching conditions at three loops
• The (alpha_s)^3 approximation of Quantum Chromodynamics to the Ellis-Jaffe sum rule
• QCD Analysis of Hadronic $\tau$ Decays Revisited
• Measurement of the tau- --> K- pi0 nu_tau Branching Fraction
• A Study of Ultraviolet Renormalon Ambiguities in the Determination of $\as$ from $\tau$ Decay
• Improved Calculation of F2 in Electroproduction and xF3 in Neutrino Scattering to NNLO and Determination of alpha_s
• Strong coupling constant from $\tau$ decay within renormalization scheme invariant treatment
• RS-invariant all-orders renormalon resummations for some QCD observables
• Wess-Zumino Current and the Structure of the Decay tau^- to K^-K^+ pi^- nu_tau
• Hadronic decays of the tau lepton into K K pion modes within Resonance Chiral Theory
• The uncertainty in ${\alpha }_s(M_Z^2)$ determined from hadronic tau decay measurements
• Measurement of the Strong Coupling alpha_s from the Four-Jet Rate in e+e- Annihilation using JADE data
• Renormalization scheme dependence and the problem of determination of alpha_s and the condensates from the semileptonic tau decays

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