Lepton Flavour Universality measurements and flavour anomalies at LHCb

This document presents two new results of the LHCb experiment investigating $B$ flavour anomalies. The first result provides a new measurement of the branching fraction ratios $R(D^+)$ and $R(D^{\ast +})$ using muonic $\tau$ decays as a test of lepton flavour universality. The second result offers a comprehensive analysis of local and nonlocal amplitudes in the rare $B^0 \to K^{\ast 0}\mu^+\mu^-$ decay, disentangling potential New Physics contributions from Standard Model nonlocal effects. Both analyses yield results compatible with previous measurements, with the tension between theory and experiment in $R(D^{(\ast)})$ reaching a significance of $3.2\sigma$. Furthermore, a $2.1\sigma$ deviation in the Wilson coefficient $C_9$ is observed in the $B^0 \to K^{\ast 0}\mu^+\mu^-$ decay. These measurements contribute to the growing body of evidence hinting at possible New Physics contributions in $B$ meson decays.