$\alpha_s(m_\tau)$ from an improved vector isovector spectral function
December 01, 2022
June 15, 2023
We discuss a new determination of the strong coupling at the $\tau$-mass scale, $\alpha_s(m_\tau^2)$, based on a new vector isovector spectral function, which combines ALEPH and OPAL spectra for the dominant $2\pi$ and $4\pi$ decay channels with estimates for several sub-leading contributions obtained using CVC from recently measured electroproduction cross-sections, as well as results for $\tau\to K^- K^0\nu_\tau$ obtained by BaBar. This fully inclusive vector isovector spectral function is entirely based on experimental data, and no longer relies on Monte Carlo input for any of the sub-leading modes. We obtain $\alpha_s(m_\tau)=0.3077\pm 0.0075$, corresponding to $\alpha_s(m_Z)=0.1171\pm 0.0010$.
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating
very compact bibliographies which can be beneficial to authors and
readers, and in "proceeding" format
which is more detailed and complete.