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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{cb}|$ is extractedfrom exclusive semileptonic $B \to D^{(*)}$ decays adopting a novelunitarity-based approach which allows to determine in a full non-perturbativeway the relevant hadronic form factors (FFs) in the whole kinematical range. Byusing existing lattice computations of the $B \to D^{(*)}$ FFs at small recoilfrom FNAL/MILC and JLQCD Collaborations, we show that it is possible toextrapolate their behavior also at large recoil without assuming any specificmomentum dependence and without constraining their shape using experimentaldata. Thus, we address the extraction of $|V_{cb}|$ from the experimental dataon the semileptonic $B \to D^{(*)} \ell \nu_\ell$ decays, obtaining $\vertV_{cb}\vert = (41.0 \pm 1.2 ) \cdot 10^{-3}$ from $B \to D$ using as input thefinal FNAL/MILC lattice data for the FFs and $|V_{cb}| = (40.4 \pm 1.8 ) \cdot10^{-3}$ from $B \to D^*$ using the preliminary JLQCD lattice data. Our resultfrom $B \to D$ is consistent within $\sim 1$ standard deviation with the mostrecent inclusive determination $|V_{cb}|_{incl} = (42.00 \pm 0.65) \cdot10^{-3}$. The resulting uncertainty is comparable with those obtained inliterature using experimental data to constrain the shape of the FFs. Ourresult from $B \to D^*$, though consistent with $|V_{cb}|_{incl} $, is stillbased on preliminary lattice data for the FFs and its uncertainty is greaterthan the ones obtained in literature using experimental data to constrain theshape of the FFs. We investigate also the issue of Lepton Flavor Universalitythanks to new theoretical estimates of the ratios $R(D^{(*)})$, namely $R(D) =0.296(8)$ using final FNAL/MILC lattice results, and $R(D^{*}) = 0.261(20)$using preliminary JLQCD and FNAL/MILC lattice data. Our findings differ by$\sim 1.4\sigma$ from the latest experimental determinations.

$\vert V_{cb} \vert$ and $R(D^{(*)})$ using lattice QCD and unitarity