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arXiv · 1811.06470

HFLAV $\tau$ branching fractions fit and measurements of Vus with $\tau$ lepton data

Alberto Lusiani
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Abstract

We report the status of the Heavy Flavour Averaging Group (HFLAV) averages of the $\tau$ lepton measurements We then update the latest published HFLAV global fit of the $\tau$ lepton branching fractions (Spring 2017) with recent results by BABAR. We use the fit results to update the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus measurements with the $\tau$ branching fractions. We combine the direct $\tau$ branching fraction measurements with indirect predictions using kaon branching fractions measurements to improve the determination of Vus using $\tau$ branching fractions. The Vus determinations based on the inclusive branching fraction of $\tau$ to strange final states are about $3\sigma$ lower than the Vus determination from the CKM matrix unitarity.

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Alberto Lusiani. 2018-11-15. HFLAV $\tau$ branching fractions fit and measurements of Vus with $\tau$ lepton data. https://doi.org/10.21468/scipostphysproc.1.001

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