Related papers: |V_{ub}| from B-> pi e nu
We point out that current experimental data for partial B --> pi l nu branching fractions reduce the theoretical input required for a precise extraction of |V_ub| to the form factor normalization at a single value of the pion energy. We…
We discuss the calculation of the $B \rightarrow \pi$ and $D \rightarrow \pi$ form factors based on an expansion in terms of pion wave functions on the light-cone with increasing twist and QCD sum rule methods. The results are compared with…
We present results for the $B \rightarrow \pi$ and $D\rightarrow \pi$ form factors derived from QCD sum rules on the light-cone. Our predictions are compared with experiment and used to extract the quark mixing parameter $|V_{ub}|$ from a…
We present a lattice-QCD calculation of the $B\to\pi\ell\nu$ semileptonic form factors and a new determination of the CKM matrix element $|V_{ub}|$. We use the MILC asqtad 2+1-flavor lattice configurations at four lattice spacings and…
I review the current status of the determination of Vus from a lattice perspective. The recent progress are very impressive: computation with 2 + 1 and 2 + 1 + 1 dynamical flavours, physical pion mass, several fine lattices, different…
In this article, we calculate the $B\to a_1(1260)$ form-factors $V_1(q^2)$, $V_2(q^2)$, $V_3(q^2)$ and $A(q^2)$ with the $B$-meson light-cone QCD sum rules. Those form-factors are basic parameters in studying the exclusive non-leptonic…
We report on the perturbative $O(\alpha_s)$ correction to the light-cone QCD sum rule for the $B\to \pi$ transition form factor $f^+$. The correction to the product $f_Bf^+$ in leading twist approximation is found to be about 30%, that is…
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…
In this article, we calculate the vector form factors $f^+_{K\pi}(Q^2)$ and $f^-_{K\pi}(Q^2)$ within the framework of the light-cone QCD sum rules approach. The numerical values of the $f^+_{K\pi}(Q^2)$ are compatible with the existing…
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…
A systematic analysis shows that the main uncertainties in the form factors are due to the twist-3 wave functions of the light mesons in the light-cone QCD sum rules. We propose an improved approach, in which the twist-3 wave functions…
The 2012 PDG reports a tension at the level of $3 \sigma$ between two exclusive determinations of $|V_{ub}|$. They are obtained by combining the experimental branching ratios of $B \to \tau \nu$ and $B \to \pi l \nu$ (respectively) with a…
We develop a new method in lattice QCD to calculate the form factor F(1) at zero recoil. This is the main theoretical ingredient needed to determine |V(cb)| from the exclusive decay anti-B --> D* lepton anti-neutrino. We introduce three…
We present a QCD light-cone sum rule (LCSR) estimation of the B -> pi, B -> K, and Bs -> K form factors calculating gluon radiative corrections at next-to-leading order. The MS-bar b-quark mass is used, instead of the one-loop pole mass…
We calculate the $B \to\pi\ell\nu$ and $B_s \to K \ell\nu$ form factors in dynamical lattice QCD. We use the (2+1)-flavor RBC-UKQCD gauge-field ensembles generated with the domain-wall fermion and Iwasaki gauge actions. For the $b$ quarks…
The form factors of the semileptonic $B\to \pi\pi\ell\bar\nu$ decay are calculated from QCD light-cone sum rules with the distribution amplitudes of dipion states. This method is valid in the kinematical region, where the hadronic dipion…
We use Omnes representations of the form factors f_+ and f_0 for exclusive semileptonic B to pi decays, paying special attention to the treatment of the B* pole and its effect on f_+. We apply them to combine experimental partial branching…
We describe the calculation of the $B\rightarrow \pi$ hadronic matrix element from operator product expansion near the light-cone in QCD. In the resulting sum rules, the form factors $f^+$ and $F_0$ determining this matrix element are…
We present the current status of the computation of the form factor $f_+ (q^2)$ for the semi-leptonic decay $\mathrm B_\mathrm s \to \mathrm K \ell \nu$ by the ALPHA collaboration. We use gauge configurations which were generated as part of…
After improving the knowledge about residua of the semileptonic form factor at its first two poles we show that $f_+^{D\pi}(q^2)$ is not saturated when compared with the experimental data. To fill the difference we approximate the rest of…