After discussing difficulties in determining αs from tau decay due to the existence of Duality Violations and the associated asymptotic nature of the OPE, we describe a new determination based on an improved vector isovector spectral function, now based solely on experimental input, obtained by (i) combining ALEPH and OPAL results for 2π+4π and (ii) replacing K−K0 and higher-multiplicity exclusive-mode contributions, both previously estimated using Monte Carlo, with new experimental BaBar results for K−K0 and results implied by e+e− cross sections and CVC for the higher-multiplicity modes. We find αs(mτ)=0.3077±0.0075, which corresponds to αs(mZ)=0.1171±0.0010. Finally, we comment on some of the shortcomings in the criticism of our approach by Pich and Rodriguez-Sanchez.
@article{arxiv.2210.13518,
title = {$\alpha_s$ from an improved $\tau$ vector isovector spectral function},
author = {Diogo Boito and Maarten Golterman and Kim Maltman and Santiago Peris and Marcus V. Rodrigues and Wilder Schaaf},
journal= {arXiv preprint arXiv:2210.13518},
year = {2023}
}
Comments
Contribution to the proceedings of The XVth Quark Confinement and the Hadron Spectrum Conference, August 1st-6th, 2022, Univ. of Stavanger, Norway