Related papers: Improving the Kpi vector form factor through Kl3 c…
We present a study of the decay tau- -> K_S pi- nu_tau using a 351 fb^-1 data sample collected with the Belle detector. The analysis is based on 53110 lepton-tagged signal events. The measured branching fraction B(tau- -> K_S pi-…
We propose a description of the $K^+$, $K_S$ radiative decay form factors $W_+$, $W_S$ based on general properties of analyticity and unitarity. Starting from the simple consideration of the asymptotic behaviour of the two combinations…
Quark model results for the $B\to \pi,\rho$ decays are analysed, making use of the dispersion formulation of the model: The form factors at $q^2>0$ are expressed as relativistic invariant double spectral representation over invariant masses…
The semileptonic $B\to \pi l^+ \nu_l$ decay is studied starting from a simple quark model which includes the influence of the $B^*$ pole. To extend the predictions of a nonrelativistic constituent quark model from its region of…
We consider the lowest order radiative corrections for the decay $K^{\pm}\to \pi^0 e^{\pm} \nu$, usually referred as $K_{e3}^{\pm}$ decay. This decay is the best way to extract the value of the $V_{us}$ element of the CKM matrix. The…
Using 214 fb-1 of data recorded by the Babar detector at the PEPII electron-positron collider, we study the decay Ds+ --> K+ K- e+ nu. Except for a small S-wave contribution, the events with K+K- masses in the range 1.01-1.03 GeV/c2…
The ratio of the $K^{+}\to \pi^{0} \mu^{+} \nu$ ($K_{\mu3}^+$) and $K^{+}\to \pi^{0} e^{+} \nu$ ($K_{e3}^+$) decay widths, $\Gamma(K_{\mu 3})/\Gamma(K_{e3})$, has been measured with stopped positive kaons. $K_{\mu3}^+$ and $K_{e3}^+$…
A calculation of the semi--leptonic decays of the kaon ($K_{l3}$) is presented. The results are direct predictions of a covariant model of the pion and kaon introduced earlier by Ito, Buck, Gross. The weak form factors for $K_{l3}$ are…
Using the light-front quark model, we calculate the transition form factors, decay rates, and longitudinal lepton polarization asymmetries for the exclusive rare $B\to K\ell^+\ell^-(\ell=e,\mu,\tau$) decays within the standard model.…
By analyzing all existing measurements for $ D\rightarrow K \ell^+ \nu_{\ell} $ ( $\ell=e,\ \mu$ ) decays, we find that the determinations of both the vector form factor $f_+^K(q^2)$ and scalar form factor $f_0^K(q^2)$ for semileptonic…
We investigate the form factors and decay rates for the semileptonic decays of the kaon($K_{l3})$ using the light-front quark model. The form factors $f_{\pm}(q^{2})$ are calculated in $q^{+}=0$ frame and analytically continued to the…
We present a new calculation of the B->pi form-factor f_+, relevant for the measurement of |V_{ub}| from semileptonic B->pi transitions, from QCD sum rules on the light-cone. The new element is the calculation of radiative corrections to…
The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the meson bound state amplitudes and the dressed quark-W vertex in a manifestly covariant calculation of the K_{l3}…
Armed with the information on the form factor $\fdpi(0)$ inferred from recent CLEO measurements of SU(3)-breaking effects in charmed meson decays, we have studied the form factor $\fbpi$. In the heavy quark limit, $\fbpi(q^2)$ is related to…
We calculate the long-distance radiative corrections \delta^e_{LD} and \delta^{\mu}_{LD} to the K^0 -> \pi^- e^+ \nu_e and the K^0 -> pi^- \mu^+ \nu_{\mu} decay rates. This analysis includes contributions to the long-distance radiative…
The form factors for semi-leptonic B decays, $\bar{B}\to\pi l\bar{\nu}_l$, are calculated under collinear factorization approach. The end-point divergences are regularized by a $\xi$-regularization, where $\xi$ means the collinear fraction…
We present a measurement of the ratio of the decay rates Gamma(KL -> pi+ pi-)/Gamma(KL -> pi e nu), denoted as Gamma(K2pi)/Gamma(Ke3). The analysis is based on data taken during a dedicated run in 1999 by the NA48 experiment at the CERN…
We present a new calculation of the $D\to\pi$ and $D \to K$ form factors from QCD light-cone sum rules. The $\overline{MS}$ scheme for the $c$-quark mass is used and the input parameters are updated. The results are $f^+_{D\pi}(0)=…
The first measurements of the coherence factors (R_Kpipi0 and R_K3pi) and the average strong-phase differences (delta_D^Kpipi0 and delta_D^K3pi) for D0->K-pi+pi0 and D0->K-pi+pi+pi- are presented. These parameters can be used to improve the…
Our article is devoted to the study of the rare $B\to K^\ast \ell^+\ell^-$~decay where $\ell=e,\mu,\tau$. We compute the relevant form factors in the framework of the covariant quark model with infrared confinement in the full kinematical…