Determination of the quark coupling strength |v$_{ub}$| using baryonic decays

A measurement of the ratio of branching fractions between $\Lambda^0_b \to p\mu^- \bar{\nu}_\mu$ and $\Lambda^0_b \to \Lambda^+_c \mu^-\bar{\nu}_\mu$ decays is performed using data corresponding to $2fb^{-1}$ of integrated luminosity, collected by the LHCb detector in 2012. This combined with the latest form factor predictions obtained from lattice QCD calculations leads to the first determination of $|V_{ub}|$ at a hadron collider and in a baryon decay, $|V_{ub}|$ = (3.27 ± 0.23) x $10^{-3}$, The measurement is consistent with existing exclusive measurements made using $B^0 \to \pi^+ \mu^- \bar{nu}_\mu$, but disagrees with those made inclusively.