Lepton Flavor Violation in B decays

International audienceThe RK measurement by LHCb suggests non-standard lepton non-universality (LNU) to occur in $ b\to sl^+ l^- $ transitions, with effects in muons rather than electrons. A number of other measurements of $ b\to sl^+ l^- $ transitions by LHCb and $B$-factories display disagreement with the Standard- Model predictions and, remarkably, these discrepancies are consistent in magnitude and sign with the $R_{\scriptscriptstyle K}$ effect. Non-standard LNU suggests non-standard lepton flavor violation (LFV) as well. We discuss several B-physics observables to measure such LFV effects