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|V_us| from Strange Hadronic Tau Data

Elvira Gamiz·Matthias Jamin·Antonio Pich·Joaquim Prades·Felix Schwab
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Abstract

We report on recent work to determine the CKM matrix element |V_{us}| using strange hadronic τdecay data. We use the recent OPAL update of the strange spectral function, while on the theory side we update the dimension-two perturbative contribution including the recently calculated α_s^3 terms. Our result |V_{us}|=0.2220 \pm 0.0033 is already competitive with the standard extraction from K_{e3} decays and other new proposals to determine |V_{us}|. The actual uncertainty on |V_{us}| from τdata is dominated largely by experiment and will eventually be much reduced by B-factories and future τ-charm factory data, providing one of the most accurate determinations of this Standard Model parameter.

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Elvira Gamiz, Matthias Jamin, Antonio Pich, Joaquim Prades, Felix Schwab. 2006-10-19. |V_us| from Strange Hadronic Tau Data. https://doi.org/10.1142/9789812790873_0161

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