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KLOE extraction of Vus from kaon decays and lifetimes

B. Sciascia
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Abstract

The most precise determination of Vus comes from semileptonic kaon decays. The KLOE experiment at DA\PhiNE the Frascati ϕ-factory, has measured all the exeperimental inputs to Vus for both neutral and charged kaons. Preliminary results for BR(K^\pm\toπ^0 e^\pmν) and BR(K^\pm\toπ^0 μ^\pmν), and for τ_\pm are presented, together with measurements of the K_Le3 and K_L\mu3 decay BR, the K_Se3 decay BR and the K_L lifetime τ_L. From our results for the 5 braching ratios and τ_L we find Vus=0.2258\pm0.0022. We have also measured the fully inclusive K^+\mu2(γ) absolute branching ratio for which we obtain BR(K^+\toμν(γ))=0.6366\pm0.0017. Combining this value with recent lattice results for f_K/f_πgives Vus=0.2223\pm0.0026.

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B. Sciascia. 2005-10-10. KLOE extraction of Vus from kaon decays and lifetimes. https://arxiv.org/abs/hep-ex/0510028

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