Charged lepton flavour violation search with the MEGII and the Mu3e experiments at PSI
Dr. Angela Papa (PSI, Villigen, Switzerland and University of Pisa/INFN, Italy)

Lepton flavor violation (LFV) research is currently one of the most exciting branches of particle physics due to its high sensitivity to new physics. The observation of neutrino oscillations has clearly demonstrated that neutral lepton flavor is not conserved. This implies that charged LFV (cLFV) processes, such as the µ⁺ --> e⁺γ decay or the µ⁺ --> e⁺ e⁺ e⁻ decay, can also occur in simple extended Standard Model (SM) versions (i.e. including Dirac neutrinos) which takes into account for neutrino oscillations, although strongly suppressed. On the other hand, Beyond SM (BSM) extensions strongly enhance the predictions for cLFV branching ratios. Therefore such decays are ideal probes for new physics.

In this talk the current status of the MEGII and the Mu3e experiments will be given. The first will aim at searching for the µ⁺ --> e⁺γ decay with a sensitivity of approx. 6 x10⁻¹⁴ while the second will pursue the µ⁺ --> e⁺ e⁺ e⁻ − decay search with an ultimate sensitivity of 10⁻¹⁶. Both experiments will be hosted at the Paul Scherrer Institut (Villigen, Switzerland) which delivers the most intense low energy continuous muon beam in the world (up to few x10⁸ µ/s), the optimal choice for such a kind of search. It will be also discussed the potentialities of these apparatuses to search for more exotics processes.