$|V_{ub}|$ using $\Lambda_b \rightarrow p \mu^- \overline\nu_\mu$ decays at LHCb

A measurement of the ratio of branching fractions between $ \Lambda^0_b \rightarrow p\ \mu^- \bar{\nu} $ and $ \Lambda^0_b \rightarrow \Lambda_c^+ \mu^-\bar{\nu} $ decays is performed using data corresponding to 2fb$^{-1}$ of integrated luminosity, collected by the LHCb detector. This combined with the latest form factor predictions obtained from lattice QCD calculations leads to the first determination of $\vert V_{ub} \vert$ at a hadron collider and in a baryon decay. The measurement achieves a relative precision of 7.3% which is more precise than any existing published exclusive measurements.