Related papers: Analysis of the QCD-improved factorization in B ->…
We consider rare semileptonic decays of a heavy $D$-meson into a light vector meson in the framework of QCD factorization. In contrast to the corresponding $B$-meson decays, the naive factorization hypothesis does not even serve as a first…
In this note, we calculate the branching ratio of B_c\to J/\psi K in the framework of perturbative QCD approach based on k_T factorization. This decay can occur only via tree level diagrams in the Standard Model. We find that the branching…
We provide updated predictions for the hadronic decays $\bar{B}_s^0\to D_s^{(*)+} \pi^-$ and $\bar{B}^0\to D^{(*)+} K^-$. They are based on $\mathcal{O}(\alpha_s^2)$ results for the QCD factorization amplitudes at leading power and on…
We derive the $k_T$ resummation for doubly heavy-flavored $B_c$ meson decays by including the charm quark mass effect into the known formula for a heavy-light system. The resultant Sudakov factor is employed in the perutrbative QCD study of…
In order to obtain information about the Standard Model from exclusive hadronic two-body B-decays, we have to quantify non-perturbative QCD effects. Approaches based on the factorization of mass singularities into hadronic distribution…
The rare Higgs boson decay $H\to Z\gamma$ is forbidden at tree-level. In the Standard Model, it is loop-mediated through a $W$ boson or a heavy quark. We analytically compute the QCD correction to the heavy quark loop, confirming earlier…
The radiative leptonic $B\to \gamma\ell\nu_{\ell}$ decay serves as an ideal platform to determine the $B$-meson inverse moment which is a fundamental nonperturbative parameter for the $B$ meson. In this paper, we explore precise QCD…
Two-body weak decays / and are examined under isospin analysis to study nonfactorizable contributions. After extracting the strong phases and obtaining the factorizable contributions from spectator-quark diagrams for Nc=3, we determine…
We show that the amplitudes for B decays into two light mesons at leading order in soft-collinear effective theory are factorized to all orders in alpha_s. We construct gauge-invariant four-quark operators by employing the effective…
We compute next-to-next-to-leading order QCD corrections to the partonic processes $b\to c \bar{u} d$ and $b\to c \bar{c} s$, which constitute the dominant decay channels in standard model predictions for $B$-meson lifetimes within the…
We study the high-energy limit of the scattering amplitudes suppressed by the leading power of the quark mass in perturbative quantum chromodynamics. We prove the factorization and perform all-order resummation of the double-logarithmic…
We present a systematic study of the B meson light-cone distribution amplitudes which are relevant for the QCD factorization approach for the exclusive B meson decays. We construct representations for the quark-antiquark distribution…
The perturbative QCD corrections to the nonleptonic decay rate of the $b$ quark are discussed. By considering the limit where the final charmed quarks are slow, it is argued that the coefficients of the $\alpha_s^2$ terms, corresponding to…
It is hoped that the accuracy of a variety of lattice calculations will be improved by perturbatively eliminating effects proportional to the lattice spacing. In this paper, we apply this improvement program to the heavy quark effective…
Recent theoretical investigations of two-body hadronic B decays have provided justification for the use of the factorization ansatz to evaluate the B decay matrix elements. Motivated by this, we present simplified formulae for a wide range…
We discuss the form factors of the heavy-to-light transitions $B \ra \pi$ and $D\ra \pi$, the $B^*B \pi$ and $D^*D \pi$ coupling constants, and the nonfactorizable amplitude of the decay $ B \ra J/\psi K$ in the framework of QCD sum rules.
These notes provide a pedagogical introduction to the theory of non-leptonic heavy-meson decays recently proposed by Beneke, Buchalla, Sachrajda and myself. We provide a rigorous basis for factorization for a large class of non-leptonic…
We report on the construction of a factorization theorem for the contribution of the electromagnetic dipole operator ${\cal O}_7$ to the $\bar B_s \to \mu^+\mu^-$ decay amplitude. The leading-order contribution from a QED box diagram…
We derive the QCD$\times$QED factorization theorem governing the leptonic decay $B^-\to\mu^-\bar\nu_\mu(\gamma)$ at all orders in $\alpha_s$ and $\alpha$. Electromagnetic corrections to this decay probe multiple scales, which we disentangle…
We calculate, for the first time using unquenched lattice QCD, form factors for the rare decay B -> Kll in and beyond the Standard Model. Our lattice QCD calculation utilizes a nonrelativistic QCD formulation for the b valence quarks, the…