相关论文: Constraining weak annihilation using semileptonic …
Charmless semileptonic decays, ${\bar{B}} \to X_u \ell \bar{\nu}$, are studied in a sample of 232 million $B\bar{B}$ decays recorded with the BaBar detector, in events where the decay of the second $B$ meson is fully reconstructed.…
We determine $|V_{cb}|$ from inclusive semileptonic B decays including resummation of supposedly large perturbative corrections, which originate from the running of the strong coupling. We argue that the low value of the BLM scale found…
The recent theoretical progress in the description of semileptonic decays in the framework of the heavy mass expansion is summarized. Both inclusive and exclusive decays are considered.
In this paper, we analyze different decay observables of semileptonic $ B_c$ decays into $(D_(s,d)^((*))){\mu}^+ {\mu}^-$ such as branching ratio, forward-backward asymmetry, polarization fraction and lepton polarization asymmetry in the…
The semileptonic decays $\bar{B}\to D(D^*)\pi\ell\bar{\nu}$ are analyzed by heavy quark and chiral symmetries. The branching ratio is of order of a few percent for $\dpi$, but it is much smaller for $\dstar$, of order $10^{-4}-10^{-5}$. The…
We calculate the inclusive charmless semileptonic decay width of the B meson using a QCD-based approach. This approach is able to account for both dynamic and kinematic effects of nonperturbative QCD. The charmless semileptonic decay width…
A possibility is considered of explaining the low experimental value of the ratio of the lifetimes tau(Lambda_b)/tau(B_d) by a new `centiweak' four-quark interaction, i.e with a strength on the order of 10^{-2}G_F. It is noted that the…
The $b$ and the $c$ quark compete with each other in decays of the $B_c$-meson. We emphasize the need of obtaining reliable signals of $c \to s$ in order to assess the merits of the spectator approximation in calculating the relative…
This paper reviews semileptonic decays of $B$-mesons to states containing charm mesons, i.e., D, D*, D** and possible non-resonant D^{(*)}npi states as well. The paper covers measurement of branching fractions, form-factors and, most…
The form factors of the weak $B_s$ transitions to the ground state and orbitally excited strange mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. These form factors…
Motivated by recent experimental results on charm physics we investigate implications of the updated constraints of new physics in rare charm meson decays. We first reconsider effects of the MSSM in $c\to u \gamma$ constrained by the recent…
The rate of the semileptonic decay b to c l v is calculated with order alphas^2 accuracy, as an expansion around the limit of equal masses of the b and c quarks. Recent results obtained around the limit of the c-quark much lighter than b…
We calculate semileptonic form factors for the decays $B_c \to \eta_c \, l \nu$ and $B_c \to J/\psi \, l \nu$ over the entire $q^2$ range, using a highly improved lattice quark action for charm at several lattice spacings down to $a=0.045$…
Semileptonic and leptonic B decays are analyzed in the framework of the relativistic quark model. Special attention is payed to the decays involving $\tau$ lepton. It is found that the calculated particular decay branching fractions are…
The mixing between nonstrange and strange quark wavefunctions in the $\omega$ and $\phi$ mesons leads to a small predicted branching ratio $\b(D_s^+ \to \omega e^+ \nu_e) = {\cal O}(10^{-4})(\delta/3.34^\circ)^2$, where $\delta$ is the…
A field theoretic description for inclusive semileptonic B meson decays is formulated. We argue that large regions of the phase spaces for the decays are dominated by distances near the light cone. The light-cone dominance allows to…
In this paper I review the status of lattice QCD calculations of $D$ and $D_s$ meson decay constants and of $D$ meson semileptonic decay form factors. I restrict my discussion to results obtained from simulations with $n_f = 2+1$ sea…
Inclusive bottom hadron decays are analyzed based on the heavy quark effective field theory (HQEFT). Special attentions in this paper are paid to the b\to u transitions and nonspectator effects. As a consequence, the CKM quark mixing matrix…
The inclusive direct and cascade semileptonic branching ratios of the b quark were measured from a fit to the lepton momentum spectrum in the B-hadron rest frame, exploiting the charge correlation between the lepton and the heavy meson. The…
We report two novel determinations of |Vub| with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson…