Charged lepton flavour violation

Abstract

The observation of neutrino oscillations has demonstrated that individual lepton numbers are not conserved. However, lepton flavour violation has so far not been seen in processes involving charged leptons, despite many models beyond the standard model predicting sizeable rates for decays such as μ → e + γ . In this talk charged lepton flavour oscillations is briefly summarized from a theoretical point of view: (i) It is stressed that observing charged lepton flavour oscillations in different final states is important to distinguish between different models; (ii) SUSYSupersymmetric lepton flavour violation in seesaw models is briefly outlined; (iii) the impact of non-abelian symmetries for predictions of charged lepton flavour oscillations is discussed and, finally (iv) the status of the exotic decay μ → e + Majoron is summarized.