Strong coupling at the τ-mass scale from an improved vector isovector spectral function

2021/12/10 by Diogo Boito, Boito, Diogo, Maarten Golterman +9
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph

paper · pdf · doi:10.48550/arxiv.2112.05413

11 pages, 4 figures. Contribution to the Proceedings of "The 16th International Workshop on Tau Lepton Physics (TAU2021) (Virtual Edition)", from September 27th to October 1st 2021, Indiana University

arxiv created 2021/12/10 · arxiv updated 2021/12/13

Abstract

We perform a precise extraction of the QCD coupling at the τ-mass scale, α_s(m_τ), from a new vector isovector spectral function which combines ALEPH and OPAL distributions for the dominant channels, τ→ππ⁰ν_τ, τ→ 3ππ⁰ν_τ and τ→ π3π⁰ν_τ, with estimates of sub-leading contributions obtained from electroproduction cross-sections using CVC, as well as BaBar results for τ→ K^-K⁰ν_τ. The fully inclusive spectral function thus obtained is entirely based on experimental data, without Monte Carlo input. From this new data set, we obtain α_s(m_τ)=0.3077±0.0075, which corresponds to α_s(m_Z)=0.1171±0.0010. This analysis can be improved on the experimental side with new measurements of the dominant ππ⁰, π3π⁰, and 3ππ⁰ τ decay modes.

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