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V_{us} from hyperon semileptonic decays

Ruben Flores-Mendieta
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Abstract

A model-independent determination of the CKM matrix element V_{us} from five measured strangeness-changing hyperon semileptonic decays is performed. Flavor SU(3) symmetry breaking effects in the leading vector and axial-vector form factors are analyzed in the framework of the 1/N_c expansion of QCD. A fit to experimental data allows one to extract the value V_{us}=0.2199\pm 0.0026, which is comparable to the one from K_{e3} decays. This reconciliation is achieved through second-order symmetry breaking effects of a few percent in the form factors f_1, which increase their magnitudes over their SU(3) predictions.

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Ruben Flores-Mendieta. 2004-10-12. V_{us} from hyperon semileptonic decays. https://doi.org/10.1103/physrevd.70.114036

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