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

Abstract

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