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arXiv · 0901.1434

alpha_s and the tau hadronic width

Matthias Jamin
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Abstract

Different choices exist for the renormalisation group resummation in the determination of $α_s$ from hadronic $τ$ decays: namely fixed-order (FOPT) and contour-improved perturbation theory (CIPT). The two approaches lead to systematic differences in the resulting $α_s$. On the basis of a model for higher-order terms in the perturbative series, which incorporates well-known structure from renormalons, it is found that while CIPT is unable to account for the fully resummed series, FOPT smoothly approaches the Borel sum. Employing the model to determine $α_s$ yields $α_s(M_τ)=0.316 \pm 0.006$, which after evolution leads to $α_s(M_Z) = 0.1180 \pm 0.0008$.

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Matthias Jamin. 2009-01-11. alpha_s and the tau hadronic width. https://doi.org/10.1016/j.nuclphysbps.2009.03.012

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