Radiative lepton mass and muon g − 2 with suppressed lepton flavor and CP violations

The recent experimental status, including the confirmation of the muon g − 2 anomaly at Fermilab, indicates a Beyond Standard Model (BSM) satisfying the following properties: 1) it enhances the g − 2 2) suppresses flavor violations, such as μ → eγ, 3) suppresses CP violations, such as the electron electric dipole moment (EDM). In this letter, I show that the eigenbasis of the mass matrix and higher dimensional photon operators can be automatically aligned if the masses of heavy leptons are generated radiatively together with the g − 2. As a result, the muon g − 2 is enhanced but the EDM of the electron and μ → eγ rate are naturally suppressed. Phenomenology and applications of the mechanism to the B-physics anomalies are argued.

Lepton flavor violations in SUSY models for muon g − 2 with right-handed neutrinos

We consider supersymmetric (SUSY) models for the muon g − 2 anomaly without flavor violating masses at the tree-level. The models can avoid LHC constraints and the vacuum stability constraint in the stau-Higgs potential. Although large flavor violating processes are not induced within the framework of minimal SUSY standard model, once we adopt a seesaw model, sizable lepton flavor violating (LFV) processes such as μ → eγ and μ → e conversion are induced. These LFV processes will be observed at future experiments such as MEG-II, COMET and Mu2e if right-handed neutrinos are heavier than 109 GeV motivated by the successful leptogenesis. This conclusion is somewhat model independent since Higgs doublets are required to have large soft SUSY breaking masses, leading to flavor violations in a slepton sector via neutrino Yukawa interactions.

Neutrino mixings as a source of lepton flavor violations

Within the left–right symmetric model (LRM) the [Formula: see text] boson decay into the channel [Formula: see text] are investigated. The branching ratios of this decay is found in the third order of the perturbation theory. The obtained expression does not equal to zero only at the existence of the neutrino mixings. This means that from the point of view of the LRM, the nonconservations of the neutral and the charged lepton flavors have the same nature. As a result, the elucidation of the decays [Formula: see text] [Formula: see text] could provide data concerned the neutrino sector structure of the LRM. The neutrino sector parameters which could be measured in that case are as follows: (i) difference of the heavy neutrino masses; (ii) heavy–heavy neutrino mixing; (iii) heavy–light neutrino mixing.