Rare Decays

This review presents recent results on key measurements of rare B and τ decays performed at the LHC and the TeVatron. Its main focus lies on recent measurements of the decay B(s)0 → µ+µ− at the two colliders and of angular observables for the decay B0 → K*0µ+µ− at the LHC experiments ATLAS, CMS and LHCb. Furthermore, the branching fraction measurement at low dilepton masses in the channel B0 → K*0e+e− from LHCb and results on the decay B± → π±µ+µ− as well as on lepton-flavour- and baryon-number-violating rare decays of τ leptons are discussed