Related papers: Threshold Resummation in B --> X_c l nu_l Decays
We calculate the next-to-leading order QCD corrections to $B$ to scalar meson form factors from QCD light-cone sum rules with $B$ meson light-cone distribution amplitudes. We demonstrate that the $B$ meson-to-vacuum correlation functions…
Form factors of the weak $\Xi_c \to \Xi(\Lambda)$ transitions are calculated within the light cone QCD sum rules. The pollutions coming from the contribution of the negative parity $\Xi_c^*$ baryon is eliminated by considering the…
We study the radiative decay B -> gamma l nu_l in the framework of QCD factorization. We demonstrate explicitly that, in the heavy-quark limit and at one-loop order in perturbation theory, the amplitude does factorize, i.e. that it can be…
The method of QCD light-cone sum rules is used to calculate soft nonfactorizable contributions to the decay amplitude for B -> J/psi K. The result confirms expectations that in color-suppressed decays nonfactorizable corrections can be…
We resum distributions that are singular at partonic threshold (the elastic limit) in heavy quark production, in terms of logarithmic behavior in moment space. The method may be applied to a variety of cross sections sensitive to the edge…
We present a complete calculation of the Leading Order QCD corrections to the quark level decay amplitude for b -> s gamma gamma and study their relevance for both the inclusive branching ratio BR(B -> X_s gamma gamma) and for the exclusive…
The transition form factors of (D_s -> f_0 l nu), (D -> f_0 l nu) and (B_u -> f_0 l nu) decays are calculated in 3-point QCD sum rule method, assuming that "f_0" is a quark-antiquark state with a mixture of strange and light quarks. The…
Applications of QCD sum rules to exclusive decays of heavy mesons are reviewed. In detail, we discuss the calculations of the B and $D$ decay constants, the heavy-to-light form factors $f^+(p^2)$ and $f^0(p^2)$, and the strong couplings…
Form factors of the rare $\Lambda_{b}(\Lambda_{b}^*)\to N\ell^{+}\ell^{-}$ decays are calculated in the framework of the light cone QCD sum rules by taking into account of the contributions from the negative parity baryons. Using the…
We compute the normalization of the form factor entering the Bs --> Ds l nu decay amplitude by using numerical simulations of QCD on the lattice. From our study with Nf=2 dynamical light quarks, and by employing the maximally twisted Wilson…
We compute the $\alpha_s^2 n_f$ perturbative QCD contribution to semileptonic B decay, including the finite mass of the charm quark. This result provides an estimate of the size of the two-loop correction, which is found to be about 50\% of…
I present a compilation of results on B->light meson form factors from QCD sum rules on the light-cone.
We show -- by explicit computation of first-order corrections -- that the QCD factorization approach previously applied to hadronic two-body decays and to form factor ratios also allows us to compute non-factorizable corrections to…
A relativistic Coulomb-like resummation factor in QCD is suggested, based on the solution of the quasipotential equation.
We present the results of a lattice QCD calculation of the form factor relevant to B-->K*gamma decay. Our final value, T(0) = 0.24 +/- 0.03(+0.04/-0.01), is obtained in the quenched approximation, and by extrapolating T(q2=0;H-->…
A varying external field approach in QCD sum rules is formulated in a systematic way to treat the weak decay form factors and their $q^2$ dependence in the process of $B \to \rho \ell \bar\nu_\ell$. From the form factor sum rules, we can…
This article is devoted to calculating the form factors of $B_c \to D^{*}$, $B_c \to D$, $B_c \to D_s^{*}$ and $B_c \to D_s$ transitions in the framework of three-point QCD sum rules. At the QCD side, the contributions of…
We test the one-loop chiral perturbation theory formula on unquenched lattice data of pseudoscalar meson decay constants. The chiral extrapolation including the effect of the chiral logarithm is attempted and its uncertainty is discussed.
The perturbative QCD approach is based on $k_T$ factorization, including the Sudakov form factors so that to avoid the endpoint singularity. In this approach, we calculate the charmless B decays like $B\to \pi\pi$ decays etc. to produce the…
We construct an evolution equation for the $B$ meson wave functions in the $k_T$ factorization theorem, whose solutions sum the double logarithms associated with the light-cone singularities, namely, the rapidity logarithms. The derivation…