Testing the type-II seesaw mechanism with gravitational waves

TL;DR

This paper investigates gravitational waves produced during the decay of particles in the type-II seesaw model, proposing a potential way to detect the mechanism indirectly through high-frequency GW observations.

Contribution

It calculates the gravitational wave spectrum from Higgs triplet decay in the type-II seesaw model, linking GW signals to neutrino mass generation mechanisms.

Findings

GW spectrum depends on Higgs triplet mass and couplings

High-frequency GWs could serve as indirect evidence for the seesaw mechanism

Detection of these GWs offers a new probe into neutrino mass origin

Abstract

Traditional seesaw mechanisms provide an elegant theoretical framework for explaining the small yet non-zero masses of neutrinos. Nevertheless, they face significant experimental challenges, primarily because the energy scale associated with the seesaw mechanism is too high to be directly probed in terrestrial experiments. In this paper, we explore the gravitational waves (GWs) generated via graviton bremsstrahlung during the decay of seesaw particles in the early Universe. Specifically, we compute the GW spectrum resulting from the decay of the Higgs triplet within the type-II seesaw model. Our results demonstrate that the resulting GW spectrum depends sensitively on the mass of the Higgs triplet and its couplings to the Standard Model Higgs doublet and the left-handed lepton doublet. The detection of such a high-frequency GW background could offer a unique experimental window into the seesaw mechanism and provide indirect evidence for its validity.