A submission to the 2020 update of the European Strategy for Particle Physics on behalf of the COMET, MEG, Mu2e and Mu3e collaborations

Abstract

Charged-lepton flavour-violating (cLFV) processes offer deep probes for new physics with discovery sensitivity to a broad array of new physics models - SUSY, Higgs Doublets, Extra Dimensions, and, particularly, models explaining the neutrino mass hierarchy and the matter-antimatter asymmetry of the universe via leptogenesis. The most sensitive probes of cLFV utilize high-intensity muon beams to search for $\mu \to e$ transitions. We summarize the status of muon-cLFV experiments currently under construction at PSI, Fermilab, and J-PARC. These experiments offer sensitivity to effective new physics mass scales approaching O($10^4$) TeV/c${}^2$. Further improvements are possible and next-generation experiments, using upgraded accelerator facilities at PSI, Fermilab, and J-PARC, could begin data taking within the next decade. In the case of discoveries at the LHC, they could distinguish among alternative models; even in the absence of direct discoveries, they could establish new physics. These experiments both complement and extend the searches at the LHC.

Input to the update of the European Strategy for Particle; 12 pages plus addendum (9 pages)

References in corpus (1)

• Research Proposal for an Experiment to Search for the Decay μ -> eee

Cited by in corpus (5)

• Self-interacting Dark Matter via Right Handed Neutrino Portal
• The Muon Smasher's Guide
• Inverse see-saw neutrino masses in the Littlest Higgs model with T-parity
• A search for a cosmologically-relevant boson in muon decay
• Spontaneous CP Violation and Horizontal Symmetry in the MSSM: Toward Lepton Flavor Naturalness