The “Golden” cLFV channels μ → eγ and μ → eee — the high-intensity frontier

Abstract

The muon as a laboratory for studying charged lepton-flavour violation (cLFV) has proven to be one of the most sensitive areas to probe for “New Physics”, due to the muon’s copious production rate and relatively long lifetime. The search at the intensity frontier with precision-type experiments is complementary to the search for new particles at the high-energy frontier of TeV colliders. Of the three “golden” muon channels: μ → eγ, μ → 3e and μ → e conversion, an overview of the status of the coincidence experiments MEG, together with the latest results, which constitute the most stringent limit to date on this decay and the recently initiated Mu3e experiment, will be given.