相关论文: CLEO results on |V_cb| and |V_ub|
I present two recent pieces of work on semileptonic $B \to \pi, \rho$ decays where it is shown how lattice QCD calculations can be used to test heavy-quark symmetry and determine phenomenologically relevant quantities despite the limits on…
This article explores the calculation of non-perturbative parameters present in the matrix element of semileptonic inclusive $B$ decays. These are important for the inclusive determination of the Cabbibo-Kobayashi-Maskawa (CKM) parameters…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility, Belle, at the Japanese KEK laboratory. The main operation of SuperKEKB has started in March 2019, and…
We present final measurements of thirteen charmless hadronic B decay modes from the CLEO experiment. The decay modes include the ten pipi, Kpi, and KKbar final states and new limits on dibaryonic final states, ppbar, pLambdabar, and…
We address the nonperturbative calculation of the inclusive decay rate of semileptonic $B_{(s)}$-meson decays from lattice QCD. Precise Standard-Model predictions are key ingredients in searches for new physics, and this type of computation…
Recent results from the CLEO Collaboration on both inclusive and exclusive radiative $B$ decays are used to constrain the parameter space of two versions of the Left-Right Symmetric Model. In the first scenario, when the left- and…
We present a reconstruction of the semileptonic decays $B^0 \to \pi^- e^+ \nu_e$ and $B^+ \to \pi^0 e^+ \nu_e$ in a sample corresponding to 189.3 fb$^{-1}$ of Belle II data, using events where the partner $B$-meson is reconstructed from a…
We report updates on two analyses of inclusive semileptonic B decays based on a dataset of 89 million BB events recorded with the BABAR detector at the Y(4S) resonance. Events are selected by fully reconstructing the decay of one B meson…
The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element $V_{ub}$ using inclusive and exclusive decays is performed with the full Belle data set at the $\Upsilon(4S)$ resonance,…
In order to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}| from B -> X_u l anti-nu_l decays, the overwhelming background from B -> X_c l anti-nu_l decays must be reduced by appropriate acceptance cuts. We study the…
Semi-leptonic $B_s \to K \ell \nu$ and $B_s \to D_s \ell \nu$ decays provide an alternative $b$-decay channel to determine the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ or to obtain $R$-ratios to investigate lepton flavor universality…
Using 3.3 Million $B\bar B$ pairs accumulated with the CLEO detector CLEO has measured ${\cal B}(B^0\to K^+\pi^-) = (1.5^{+ 0.5}_{-0.4}\pm 0.1\pm 0.1)\times 10^{-5}$, ${\cal B}(B^+\to K^0\pi^+) = (2.3^{+1.1}_{-1.0}\pm 0.2\pm 0.2)\times…
The magnitude of the Cabibbo-Kobayashi-Maskawa matrix element Vcb has been measured using B0 to D*l nu decays recorded on the Z0 peak using the OPAL detector at LEP. The D* to D0 pi+ decays were reconstructed both in the particular decay…
Exclusive semileptonic B decays are discussed. The emphasis is on using semileptonic decays to determine |V_{ub}| and |V_{cb}|. Recent progress in our understanding of B semileptonic decays to excited charmed mesons is also reviewed.
Semileptonic, B --> pi l,nu, decays are studied on the MILC dynamical configurations using NRQCD heavy and Asqtad light quarks. We work with light valence quark masses ranging between m_s and m_s/8. Preliminary simple linear chiral…
A precise determination of |V_{ub}| can be obtained exploiting the sum rule for inclusive charmless semileptonic B-meson decays. The sum rule is derived on the basis of light-cone expansion and b-flavored quantum number conservation. The…
We present a measurement of the branching fraction for the semileptonic B decay Bbar -> D+l-nubar, where l- can be either an electron or a muon. We find Gamma(Bbar -> D+l-nubar)= (13.79+/-0.76+/-2.51) ns^{-1}, and the resulting branching…
The measured $\bar{B}\to D^{(*)} l \bar\nu$ decay rates for light leptons ($l=e,\mu$) constrain all $\bar{B}\to D^{(*)}$ semileptonic form factors, by including both the leading and ${\cal O}(\Lambda_{\text{QCD}}/m_{c,b})$ subleading…
We have tried to measure $|V_{ub}|$ using inclusive semileptonic decay measurements with three different methods. The full reconstruction tag is the one of the most feasible method to measure inclusive process. Semileptonic $B\to…
We summarize the status of $|V_{cb}|$ and $|V_{ub}|$ determinations, including the long standing tension among exclusive and inclusive determinations. We also discuss $B$ meson semileptonic decays to excited states of the charm meson…