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We present the first unquenched lattice-QCD calculation of the form factors for the decay $Bto D^astell u$ at nonzero recoil. Our analysis includes 15 MILC ensembles with $N_f = 2+1$ flavors of asqtad sea quarks, with a strange quark mass close to its physical mass. The lattice spacings range from $aapprox 0.15$ fm down to $0.045$ fm, while the ratio between the light- and the strange-quark masses ranges from 0.05 to 0.4. The valence b and c quarks are treated using the Wilson-clover action with the Fermilab interpretation, whereas the light sector employs asqtad staggered fermions. We extrapolate our results to the physical point in the continuum limit using rooted staggered heavy-light meson chiral perturbation theory. Then we apply a model-independent parametrization to extend the form factors to the full kinematic range. With this parametrization we perform a joint lattice-QCD/experiment fit using several experimental datasets to determine the CKM matrix element $|V_{cb}| = (38.40 pm 0.66_{text{th}} pm 0.34_{text{exp}}) times 10^{-3}$, where the first error is theoretical and the second comes from experiment. This result is still in tension with current inclusive determinations, but it is in agreement with previous exclusive determinations. We also integrate the differential decay rate obtained solely from lattice data to predict $R(D^ast) = 0.265 pm 0.013$, which confirms the current tension between theory and experiment.
We present the first unquenched lattice-QCD calculation of the hadronic form factors for the exclusive decay $overline{B} rightarrow D ell overline{ u}$ at nonzero recoil. We carry out numerical simulations on fourteen ensembles of gauge-field config
Lattice calculations of the form factors for the charm semileptonic decays D to K l nu and D to pi l nu provide inputs to direct determinations of the CKM matrix elements |V(cs)| and |V(cd)| and can be designed to validate calculations of the form fa
We present nearly final results from our analysis of the form factors for $Bto D^astell u$ decay at nonzero recoil. Our analysis includes 15 MILC asqtad ensembles with $N_f=2+1$ flavors of sea quarks and lattice spacings ranging from $aapprox0.15$ fm
We present preliminary blinded results from our analysis of the form factors for $Brightarrow D^astell u$ decay at non-zero recoil. Our analysis includes 15 MILC asqtad ensembles with $N_f=2+1$ flavors of sea quarks and lattice spacings ranging from
The current status of the lattice-QCD calculations of the form factors of the $Bto D^astell u$ semileptonic decay is reviewed. Particular emphasis is given to the most mature calculation at non-zero recoil coming from the Fermilab Lattice and MILC co