Strongly coupled inert scalar sector with radiative neutrino masses

Abstract: We explore the phenomenological implications of a model with an extended scalar sector, incorporating strongly coupled inert Higgs doublets. The model introduces three Higgs doublets: one interacting with the $SU(2)$ symmetry of the Standard Model and two inert doublets belonging to a strongly interacting sector, within the $SU(2)_2 \times SU(2)_1 \times U(1)_Y$ electroweak gauge symmetry, which is supplemented by the spontaneously broken $\mathbb{Z}_2$ and preserved $\mathbb{Z}_2'$ discrete symmetries. In this model, the top quark and exotic fermion masses arise from renormalizable Yukawa interactions at tree level, the masses of the SM charged fermions lighter than the top quark are generated via a tree-level seesaw mechanism, and the tiny neutrino masses emerge from a one-loop-level radiative seesaw mechanism. The model is consistent with constraints from charged lepton flavor-violating processes, electroweak precision observables, and the Higgs diphoton decay rate, as well as with the constraints resulting from the Higgs trilinear self-coupling. Furthermore, it successfully complies with the constraints arising from the $95$ GeV diphoton excess.