Loop-generated neutrino masses in composite Higgs models

Abstract

We present a composite scotogenic model for neutrino masses, which are generated via loops of ℤ₂-odd composite scalars. We consider three different approaches to the couplings of the neutrinos (including three right-handed singlets) and the composite sector: ETC-like four-fermion interactions, fundamental partial compositeness and fermion partial compositeness. In all cases, the model can feature sizeable couplings and remain viable with respect to various experimental constraints if the three ℤ₂-odd right-handed neutrinos have masses between the TeV and the Planck scales. Additionally, the lightest ℤ₂-odd composite scalar may play the role of Dark Matter, either via thermal freeze-out or as an asymmetric relic. This mechanism can be featured in a variety of models based on vacuum misalignment. For concreteness, we demonstrate it in a composite two-Higgs scheme based on the coset SU(6)/Sp(6).