Gravitational waves from a scotogenic two-loop neutrino mass model

TL;DR

This paper introduces a two-loop neutrino mass model with new particles and symmetries that predicts observable gravitational waves from early Universe phase transitions, linking neutrino physics, dark matter, and gravitational wave signals.

Contribution

It presents a novel two-loop neutrino mass generation mechanism with implications for dark matter stability and gravitational wave detection.

Findings

Possible strong first-order phase transitions in the model

Predicted gravitational wave signals detectable by LISA

Constraints from lepton flavor violation and neutrino data considered

Abstract

We propose a framework to account for neutrino masses at the two-loop level. This mechanism introduces new scalars and Majorana fermions to the Standard Model. It is assumed the existence of a global $\mathrm{U(1)\times \mathcal{Z}_2}$ symmetry which after partial breaking provides the stability of the dark matter candidates of the theory. The rich structure of the potential allows for the possibility of first-order phase transitions (FOPTs) in the early Universe which can lead to the generation of primordial gravitational waves as one of the potentially observable signatures of this model. Taking into account relevant constraints from lepton flavour violation, neutrino physics as well as the trilinear Higgs couplings at next-to-leading order accuracy, we have found a wide range of possible FOPTs which are strong enough to be probed at the proposed gravitational-wave interferometer experiments such as LISA.