相关论文: HQET and Form Factor Effects in $B\to K^{(*)}\ell^…

We calculate the form factors for the semileptonic decays $B_s\to K\ell\nu$ and $B\to K\ell\ell$ with lattice QCD. We work at several lattice spacings and a range of light quark masses, using the MILC 2+1-flavor asqtad ensembles. We use the…

We calculate the transition form factors that occur in heavy $\Lambda$-type baryon semileptonic decays as e.g. in $\Lambda_{b} \to \Lambda_{c}^{+} + l^{-} + \bar{\nu}_{l} $. We use Bauer-Stech-Wirbel type infinite momentum frame wave…

Using a sample of 3.3 million B-meson decays collected with the CLEO detector at the Cornell Electron Storage Ring, we have studied $B^- \to D^0 \ell\nu$ and $\bar{B}^0 \to D^+ \ell\nu$ decays, where $\ell$ can be either an electron or…

The exclusive semileptonic $B\to K_{1}(1270) \ell^{+}\ell^{-}$ ($\ell=\mu , \tau$) decays are analyzed in variants of two Higgs double models (THDMs). The mass eigenstates $K_{1}(1270)$ and $K_{1}(1400)$ are the mixture of two axial-vector…

We update the lattice calculation of the $B\to\pi$ semileptonic form factors, which have important applications to the CKM matrix element $|V_{ub}|$ and the $B\to\pi\ell^+\ell^-$ rare decay. We use MILC asqtad ensembles with $N_f=2+1$ sea…

We have studied the decay $\bar{B} \to D\ell\bar{\nu}$, where $\ell=e or \mu$. From a fit to the differential decay rate $d\Gamma/dw$ we measure the rate normalization ${\cal F}_D(1)|V_{cb}|$ and form factor slope $\hat{\rho}^2_D$, and,…

The method of calculating electroweak decay matrix elements between heavy-heavy and heavy-light meson states is developed in the framework of relativistic quark model based on the quasipotential approach in quantum field theory. This method…

Exclusive semileptonic B decays to radially excited charmed mesons and rare radiative B decay to the orbitally excited tensor K_2^*(1430) meson are investigated in the framework of the relativistic quark model based on the quasipotential…

Inspired by the new measurements on $B^{-}\to \eta^{(\prime)}\ell \bar\nu_{\ell}$ from the BaBar Collaboration, we examine the constraint on the flavor-singlet mechanism, proposed to understand the large branching ratios for $B\to…

We study in detail the prediction for the semileptonic decays $\bar{B} \to D (D^*) \pi \ell \bar{\nu}$ by heavy quark and chiral symmetry. The branching ratio for $\bar{B} \to D \pi \ell \bar{\nu}$ is quite significant, as big as…

In this article, we calculate the $B_c^* \to \eta_c$ form-factors with the three-point QCD sum rules, then study the semileptonic decays $B_c^* \to \eta_c \ell \bar{\nu}_{\ell}$. The tiny decay widths may be observed experimentally in the…

We discuss preliminaries of a calculation of the form factors for the semileptonic decays B -> pi lv, B_s -> K lv, and B -> K ll. We simulate with NRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad configurations.…

We study the exclusive semileptonic decays $\Upsilon(1S)\to B_{(c)}\ell\bar{\nu}_\ell$, where $\ell = e,\mu,\tau$. The relevant hadronic form factors are calculated using the Covariant Confined Quark Model developed previously by our group.…

The prospects for determining $|V_{ub}|$ from exclusive B semileptonic decay are discussed. The double ratio of form factors $(f^{B\to\rho}/f^{B\to K^*})/ (f^{D\to\rho}/f^{D\to K^*})$ is calculated using chiral perturbation theory. Its…

In the context of the observed decay $B \rightarrow K^* \gamma$ the applicability of the Heavy Quark Effective Theory (HQET), treating both b and s as heavy quarks, is examined. We show that the heavy s-quark approximation, as can be found…

The energetic exclusive two-body nonleptonic decays of B mesons are investigated in the framework of the relativistic quark model within the factorization approximation. The heavy quark expansion is used for the calculation of form factors.…

We summarize recent progress in the theory of exclusive rare and semileptonic B decays, focusing on model-independent results. The heavy-to-light form factors parameterizing these decays admit a model-independent description in two distinct…

The branching fractions of the rare weak $B\to \pi l^+l^-(\nu\bar\nu)$ and $B\to\rho l^+l^-(\nu\bar\nu)$ decays are calculated in the framework of the relativistic quark model based on the quasipotential approach. The form factors…

We compute the leading order (in alpha_s) perturbative QCD and power (1/m_b^2) corrections to the hadronic invariant mass and hadron energy spectra in the decay B \to X_s \ell^+ \ell^- in standard model using the heavy quark expansion…

Using dispersive methods, we study the $B \to \gamma^*$ form factors underlying the decay $B^- \to \ell^- \bar{\nu}_\ell \ell^{\prime-} \ell^{\prime+}$. We discuss the ambiguity that arises from a separation of the full $B^- \to \ell^-…