UpdatingVusfrom kaon semileptonic decays

We update the determination of $|V_{\mathrm{us}}|$ 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 $|V_{\mathrm{us}}|$ 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 $|V_{\mathrm{us}}|$ at a low percent level.