Abstract
Using the spectral functions measured in τ decays, we investigate the actual numerical impact of duality violations on the extraction of the strong coupling. These effects are tiny in the standard αs(\( {m}_{\tau}^2 \)) determinations from integrated distributions of the hadronic spectrum with pinched weights, or from the total τ hadronic width. The pinched-weight factors suppress very efficiently the violations of duality, making their numerical effects negligible in comparison with the larger perturbative uncertainties. However, combined fits of αs and duality-violation parameters, performed with non-protected weights, are subject to large systematic errors associated with the assumed modelling of duality-violation effects. These uncertainties have not been taken into account in the published analyses, based on specific models of quark-hadron duality.
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Pich, A., Rodríguez-Sánchez, A. Violations of quark-hadron duality in low-energy determinations of αs. J. High Energ. Phys. 2022, 145 (2022). https://doi.org/10.1007/JHEP07(2022)145
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DOI: https://doi.org/10.1007/JHEP07(2022)145