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Strong coupling at the $\tau$mass scale from an improved vector isovector spectral function
by Diogo Boito, Maarten Golterman, Kim Maltman, Santiago Peris, Marcus V. Rodrigues, Wilder Schaaf
Submission summary
Authors (as registered SciPost users):  Diogo Boito 
Submission information  

Preprint Link:  scipost_202112_00034v1 (pdf) 
Date submitted:  20211214 16:56 
Submitted by:  Boito, Diogo 
Submitted to:  SciPost Physics Proceedings 
Proceedings issue:  16th International Workshop on Tau Lepton Physics (TAU2021) 
Ontological classification  

Academic field:  Physics 
Specialties: 

Approach:  Phenomenological 
Abstract
We perform a precise extraction of the QCD coupling at the $\tau$mass scale, $\alpha_s(m_\tau)$, from a new vector isovector spectral function which combines ALEPH and OPAL distributions for the dominant channels, $\tau\to\pi \pi^0\nu_\tau$, $\tau\to 3\pi \pi^0\nu_\tau$ and $\tau\to \pi 3\pi^0\nu_\tau$, with estimates of subleading contributions obtained fromelectroproduction crosssections using CVC, as well as BaBar results for $\tau \to K^K^0\nu_\tau$. The fully inclusive spectral function thus obtained is entirely based on experimental data, without Monte Carlo input. From this new data set, we obtain $\alpha_s(m_\tau)=0.3077\pm0.0075$, which corresponds to $\alpha_s(m_Z)=0.1171\pm0.0010$. This analysis can be improved on the experimental side with new measurements of the dominant $\pi\pi^0$, $\pi 3\pi^0$, and $3\pi \pi^0$ $\tau$ decay modes.