Loop Suppression of Dirac Neutrino Mass in the Neutrinophilic Two Higgs Doublet Model

TL;DR

This paper proposes an extension to the neutrinophilic two Higgs doublet model where a one-loop mechanism suppresses Dirac neutrino masses, introduces a dark matter candidate, and suggests potential LHC signatures.

Contribution

The model introduces a new one-loop neutrino mass generation mechanism with a Z_2 symmetry, linking neutrino mass suppression and dark matter stability.

Findings

Neutrino masses are generated at one-loop level.

The model predicts a stable dark matter candidate.

Potential signatures at the LHC are discussed.

Abstract

We extend the scalar sector of the neutrinophilic two Higgs doublet model, where small masses of Dirac neutrinos are obtained via a small vacuum expectation value v_nu of the neutrinophilic SU(2)_L-doublet scalar field which has a Yukawa interaction with only right-handed neutrinos. A global U(1)_X symmetry is used for the neutrinophilic nature of the second SU(2)_L-doublet scalar field and also for eliminating Majorana mass terms of neutrinos. By virtue of an appropriate assignment of the U(1)_X-charges to new particles, our model has an unbroken Z_2 symmetry, under which the lightest Z_2-odd scalar boson can be a dark matter candidate. In our model, v_nu is generated by the one-loop diagram to which Z_2-odd particles contribute. We briefly discuss a possible signature of our model at the LHC.