Minimal 3-loop neutrino mass models and charged lepton flavor violation

Abstract

We study charged lepton flavor violation for the three most popular 3-loop Majorana neutrino mass models. We call these models "minimal" since their particle content correspond to the minimal sets for which genuine 3-loop models can be constructed. In all the three minimal models the neutrino mass matrix is proportional to some powers of Standard Model lepton masses, providing additional suppression factors on top of the expected loop suppression. To correctly explain neutrino masses, therefore large Yukawa couplings are needed in these models. We calculate charged lepton flavor violating observables and find that the three minimal models survive the current constraints only in very narrow regions of their parameter spaces.

Probing the Dark Matter of Three-loop Radiative Neutrino Mass Generation Model with the Cherenkov Telescope Array

“…Furthermore, the electrons produced from DM annihilation (mostly as secondary) can generate synchrotron radiation in the presence of the magnetic field, which could be observed as a diffuse radio emission in the present and future radio observatories like Square Kilometer Array (SKA) [82], and the sensitivity to detect such radio signal from DM in the dSphs is promising [80,81]. Therefore, a combined sensitivity study of the CTA and SKA to detect the DM in the dSphs will enable us to probe further the parameter space of the generalized KNT model [83] and other variants [84,85] of the three-loop radiative neutrino mass generation models. strument response functions provided by the CTA Consortium and Observatory, see http://www.ctaobservatory.org/science/cta-performance/ (version prod3b-v2) for more details.…”

Lower bounds on lepton flavor violating branching ratios in a radiative seesaw model

“…It indicates that the new particle mass scale will have an upper bound. On the other hand, the new particles cause lepton flavor violating (LFV) processes such as µ → eγ, τ → eγ, and τ → µγ [13][14][15], and it is more significant for the lighter new particles.…”