Related papers: Analytical approaches to the calculation of f+(0)

The most precise determination of Vus comes from semileptonic kaon decays. We have measured with the KLOE detector at DAFNE, the Frascati phi-factory, all the experimental inputs to Vus for both neutral and charged kaons. Using our results…

Important progress made this year, both in theory and in experiment, helped solving the problem of 2 sigma-deviation from the unitarity of the first row elements in the CKM matrix. Today we have, |Vus|^2 + |Vud|^2 + |Vub|^2-1 = -0.0008(13),…

The most precise determination of Vus comes from semileptonic kaon decays. We have measured with the KLOE detector at DAFNE, the Frascati phi-factory, all the experimental inputs to Vus for both neutral and charged kaons. Using our results…

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…

Till the middle of 2004 it appeared that the unitarity relation Vud^2+Vus^2+Vub^2=1 might not hold at the 2.3sigma level. At that time, however, Vus was inferred from old experimental data. Since then, a large experimental and theoretical…

We discuss preliminary results for the vector form factors $f_+^{\{\pi,K\}}$ at zero-momentum transfer for the decays $D\to\pi\ell\nu$ and $D\to K \ell\nu$ using MILC's $N_f = 2+1+1$ HISQ ensembles at four lattice spacings, $a \approx…

Recent KLOE measurements allowing the extraction of the Vus element of the CKM matrix are here briefly described. The status of the resulting value of Vus is summarized. The perspectives for the completion of ongoing analyses are discussed,…

We present a quenched lattice study of the form factors $f_+(q^2)$ and $f_0(q^2)$ of the matrix elements $<\pi | \bar{s} \gamma_\mu u | K >$. We focus on the second-order SU(3)-breaking quantity $[1 - f_+(0)]$, which is necessary to extract…

We update the extraction of |Vub| from exclusive semileptonic B to pi decays, combining experimental partial branching fraction information with theoretical form factor calculations, using the recently revised HPQCD results for the form…

By globally analyzing all existing measured branching fractions and partial rates in different four momentum transfer-squared $q^2$ bins of $D\to Ke^+\nu_e$ decays, we obtain the product of the form factor and magnitude of CKM matrix…

We present a new measurement of the branching ratio R of the decay KL -> pi e nu (Ke3), relative to all charged KL decays with two tracks, based on data taken with the NA48 detector at the CERN SPS. We measure R = 0.4978 +- 0.0035. From…

The slope and curvature parameters of the $K\pi$ vector form factor, $F_+^{K\pi}$, are fitted to the data on $\tauKpi$ and $K_{l3}$ decays yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times…

We present a lattice QCD determination of the vector form factor of the kaon semileptonic decay K -> pi l nu which is relevant for the extraction of the CKM matrix element |V_{us}| from experimental data. Our result is based on the gauge…

Using staggered fermions and twisted boundary conditions, we calculate the K meson semileptonic decay vector form factor at zero momentum transfer. The HISQ formulation is used for the valence quarks, while the sea quarks are simulated with…

Leptonic and semileptonic kaon decays represent till now the golden modes for the extraction of the Cabibbo angle from experiments, provided the relevant hadronic quantities, namely the ratio of the kaon and pion leptonic decay constants,…

We perform a combined analysis of $\tau\to K\pi \nu_\tau$ decay and $\pi K$ scattering with constraints from $K_{\ell3}$ data using a $N/D$ approach that fulfills requirements from unitarity and analyticity. We obtain a good fit of the…

The most precise determination of Vus comes from semileptonic kaon decays. The KLOE experiment at DA\PhiNE the Frascati \phi-factory, has measured all the exeperimental inputs to Vus for both neutral and charged kaons. Preliminary results…

We present a measurement of the K-pi vector current form-factor parameters for the Ke3 decay. We use 328 pb$^{-1}$ of data collected in 2001 and 2002, corresponding to about 2 million Ke3 events. Measurements of semileptonic form factors…

Using HISQ $N_f=2+1+1$ MILC ensembles with five different values of the lattice spacing, including four ensembles with physical quark masses, we have performed the most precise computation to date of the $K\to\pi\ell\nu$ vector form factor…

We present updated results for the form factors of the kaon semileptonic $(K_{\ell 3})$ decay process calculated with $N_f = 2 + 1$ nonperturbatively $O(a)$-improved Wilson quark action and Iwasaki gauge action at the physical point on…