Flavour changing charged current decays at LHCb

Semileptonic $b$-hadron decays proceed via charged-current interactions and provide powerful probes for testing the Standard Model and searching for New Physics effects. The advantages of studying such decays include the large branching fractions and reliable calculations of the hadronic matrix elements. Several features can be studied, such as the ratios of branching fractions, CKM parameters, properties of $b$-hadron production, form factor parameters and New Physics Wilson coefficients. In this contribution, LHCb measurements of branching fraction in $\Lambda \to p \mu^{-} \bar{\nu}_{\mu}$ and form factor parameters with $B^0 \to D^{*+} \mu^{-} \nu_{\mu}$ decays are presented.