Speaker
Description
Inclusive hadronic $\tau$ decays provide one of the most precise extractions of the QCD coupling, $\alpha_s$, from experimental data. For a long time, these analyses relied on ALEPH and OPAL inclusive spectral functions, which were based on measurements of the dominant decay modes but necessitated Monte Carlo simulations for subleading decay channels. We have recently demonstrated that these subleading contributions can now be obtained entirely from experiment, using CVC-related electron-positron cross-sections as well as BaBar tau-decay data. In this work, we incorporate high-statistics Belle $\tau \to \pi^-\pi^0\nu_\tau$ data to construct an updated inclusive non-strange vector spectral function. Using finite-energy sum rules, and our previously developed strategy, we determine $\alpha_s(m_Z^2) = 0.1159(14)$. We discuss why this new analysis yields a smaller central value and larger error than our previous extraction, attributing the shift primarily to updated HFLAV results for the $\pi^-3\pi^0$ branching fraction. Finally, we explore how future data could further refine this determination.
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