cLFV Searches at LHCb

The LHCb detector [1, 2] covers a pseudorapidity region of 2 < η < 5, in which most of the b and c production occurs. This feature, together with excellent tracking and particle identification systems (shown in Fig. 1), makes it an excellent machine to study very rare decays. The LHCb Collaboration has reported numerous precise measurements aimed at observing indirect signals of new physics (NP). Interesting tensions with respect to SM expectations have been seen in lepton universality tests, where branching fraction ratios involving different leptons are measured. Measurements of these ratios using B →K∗`` and B →K`` decays [3, 4] lie below their Standard Model (SM) predictions, where the ratios are defined as