Dan Moise (ICL)

Test of lepton flavour universality in beauty-quark decays

Abstract: Recent measurements of b-hadron decays involving leptons are in tension with the Standard Model (SM). They are known as flavour anomalies, and they diverge by as much as three standard deviations from their SM predictions. There are various new physics scenarios (e.g. leptoquarks) that can explain the anomalies in a coherent fashion. Although some tensions could be due to theory uncertainties, certain observables are immune to such ambiguities. One of these observables is the branching fraction ratio RK = BR(B→K𝜇𝜇)/BR(B→Kee), whose sensitivity to lepton flavour universality leads to a very clean theoretical prediction. This talk will cover the currently most precise measurement of RK, based on the proton-proton collision data collected by the LHCb experiment thus far.