Lepton flavor violation from SUSY with nonuniversal scalars

Abstract

Right-handed neutrinos in supersymmetric models can act as the source of lepton flavor violation (LFV). We present experimental implications of lepton flavor-violating processes within a supersymmetric type-I seesaw framework in the three-extra-parameter nonuniversal Higgs model (NUHM3) for large [Pontecorvo-Maki-Nakawaga-Sakata- (PMNS-) like] and small [Cabibbo-–Kobayashi-–Maskawa- (CKM-) like] Yukawa mixing scenarios. We highlight LFV predictions for the natural (low Δ_{EW}) portion of parameter space. Our numerical analysis includes full two-loop renormalization group running effects for the three neutrino masses and mass matrices. We show the projected discovery reach of various LFV experiments (i.e., Mu2e, Mu3e, MEG-II, Belle-II), and specify regions that have already been excluded by the LHC searches. Our results depend strongly on whether one has a normal sneutrino ordering (NSO) or an inverted sneutrino ordering (ISO). Natural supersymmetry (SUSY) with a NSO is already excluded by MEG-2013 results while large portions of ISO have been or will soon be tested. However, LFV processes from natural SUSY with small Yukawa mixing and an ISO seem below any projected sensitivities. A substantial amount of the remaining parameter space of models with large PMNS-like neutrino mixing will be probed by Mu2e and MEG-II experiments whereas small, CKM-like Yukawa mixing predicts LFV decays which can hide from LFV experiments.