Updating V_us from kaon semileptonic decays

Abstract

We update the determination of |V_us| using semielectronic and semimuonic decays of K mesons. A modest improvement of 15% with respect to its present value is obtained for the error bar of this matrix element when we combine the four available semileptonic decays. The combined effects of long-distance radiative corrections and nonlinear terms in the vector form factors can decrease the value of |V_us| by up to 1%. Refined measurements of the decay widths and slope form factors in the semimuonic modes and a more accurate calculation of vector form factors at zero momentum transfer can push the determination of |V_us| at a few of percent level.

19 pages, 2 figures

References in corpus (5)

• A New Approach to a Global Fit of the CKM Matrix
• K_{l3} transition form factors
• Measurement of $\Gamma (K_{\mu 3})/\Gamma (K_{e3})$ ratio using stopped positive kaons
• Semi-hadronic Tau Decays at CLEO
• The Determination of the CKM Matrix

Cited by in corpus (5)

• $K_{\ell 3}$ decays in Chiral Perturbation Theory
• Determination of m_s and |V_us| from hadronic tau decays
• New, high statistics measurement of the K+ -> pi0 e+ nu (Ke3) branching ratio
• Kaon semileptonic decay (K_{l3}) form factors from the instanton vacuum
• K_{l3} and pi_{e3} decays: radiative corrections and CKM unitarity