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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 | |
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| Preprint Link: | scipost_202112_00034v1 (pdf) |
| Date submitted: | 2021-12-14 16:56 |
| Submitted by: | Boito, Diogo |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 16th International Workshop on Tau Lepton Physics (TAU2021) |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| 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 sub-leading contributions obtained fromelectroproduction cross-sections 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.