Eur. Phys. J. Spec. Top. (2024) 233: 347-358
https://doi.org/10.1140/epjs/s11734-023-01077-z

Review

$|V_{\mathit{ub}}|$ and $|V_{\mathit{cb}}|$ from exclusive semileptonic decays

¹ Physikalisches Institut der Rheinischen Friedrich-Wilhelms-Universität Bonn, 53115, Bonn, Germany
² Gravitational Waves and Fundamental Physics (GWFP), Maastricht University, Duboisdomein 30, 6229, Maastricht, The Netherlands
³ Nikhef, Science Park 105, 1098, Amsterdam, The Netherlands

^a florian.bernlochner@uni-bonn.de

Received: 12 December 2023
Accepted: 19 December 2023
Published online: 9 February 2024

Abstract

We provide an overview on the existing determinations on $|V_{\mathit{ub}}|$ and $|V_{\mathit{cb}}|$, as well as on ratio measurements. New world averages for $|V_{\mathit{ub}}|$ from $B\to \pi \ell {\overline{\nu }}_{\ell }$ and for $|V_{\mathit{cb}}|$ from $B\to D^{\ast }\ell {\overline{\nu }}_{\ell }$ are reported, combining recent measurements and lattice QCD calculations. We combine these new values with other determinations and ratios of $|V_{\mathit{ub}}|$ and $|V_{\mathit{cb}}|$ to ascertain the current knowledge of both fundamental parameters to evaluate the compatibility with determinations from inclusive semileptonic decays. We find: $|V_{\mathit{ub}}|=(3.44\pm 0.12)\times {10}^{-3}$ and $|V_{\mathit{cb}}|=(40.84\pm 0.48)\times {10}^{-3}$ with a correlation of $\rho =0.22$. These values show a disagreement from the inclusive determinations at the 2.85 $\sigma$ level.