English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We calculate the $B \to\pi\ell\nu$ and $B_s \to K \ell\nu$ form factors indynamical lattice QCD. We use the (2+1)-flavor RBC-UKQCD gauge-field ensemblesgenerated with the domain-wall fermion and Iwasaki gauge actions. For the $b$quarks we use the anisotropic clover action with a relativistic heavy-quarkinterpretation. We analyze two lattice spacings $a \approx 0.11, 0.086$ fm andunitary pion masses as light as $M_\pi \approx 290$ MeV. We simultaneouslyextrapolate our numerical results to the physical light-quark masses and to thecontinuum and interpolate in the pion/kaon energy using SU(2) "hard-pion"chiral perturbation theory. We provide complete error budgets for the formfactors $f_+(q^2)$ and $f_0(q^2)$ at three momenta that span the $q^2$ rangeaccessible in our numerical simulations. We extrapolate these results to $q^2 =0$ using a model-independent $z$-parametrization and present our final formfactors as the $z$-coefficients and the matrix of correlations between them.Our results agree with other lattice determinations using staggered lightquarks and provide important independent cross-checks. Both $B \to\pi\ell\nu$and $B_s \to K \ell\nu$ decays enable a determination of the CKM matrix element$|V_{ub}|$. To illustrate this, we perform a combined $z$-fit of our numerical$B\to\pi\ell\nu$ form-factor data with the experimental branching-fractionmeasurements leaving the relative normalization as a free parameter; we obtain$|V_{ub}| = 3.61(32) \times 10^{-3}$, where the error includes statistical andsystematic uncertainties. This approach can be applied to $B_s\to K \ell\nu$decay to determine $|V_{ub}|$ once the process has been measuredexperimentally. Finally, in anticipation of future measurements, we makepredictions for $B \to \pi\ell\nu$ and $B_s\to K \ell\nu$ Standard-Modeldifferential branching fractions and forward-backward asymmetries.

physical review. d. particles, fields, gravitation, and cosmology/physical review. d, particles, fields, gravitation, and cosmology

$B \to \pi \ell \nu$ and $B_s \to K \ell \nu$ form factors and  $|V_{ub}|$ from 2+1-flavor lattice QCD with domain-wall light quarks and  relativistic heavy quarks