Status of lepton universality tests and searches for charged lepton violation at CMS

Lepton families and lepton flavours are central pillars of the standard model (SM). However, these fundamental symmetries are explained but not motivated.The observation of neutrino oscillations indicates that lepton flavour (LF) is not conserved in the SM, and it is possible that LF violating decays could also be observed in the charged lepton sector. Charged LF violating decays are allowed in the SM although they are extremely rare and inaccessible at current colliders.Recent measurements provide a consistent tension of lepton flavour universality (LFU) in processes that include B-decays. These could either be due to simple fluctuations or indicate first hints of the breaking of the SM.If confirmed, LFU violation would imply physics beyond the SM, such as new fundamental interactions.Here, tests of charged LFU and searches for charged LFU violating decays at the CERN LHC with the CMS experiment are presented and discussed.