Inverse Seesaw, dark matter and the Hubble tension

TL;DR

This paper explores how an inverse Seesaw model with a Majoron can address the Hubble tension and dark matter, proposing new particles and mechanisms that influence cosmological parameters and particle production.

Contribution

It introduces a scenario combining inverse Seesaw with a Majoron to simultaneously tackle the Hubble tension and dark matter within a unified framework.

Findings

Majoron contributes to ΔN_eff, alleviating Hubble tension

Sterile neutrinos can serve as dark matter via freeze-in production

Model provides a consistent particle physics explanation for cosmological observations

Abstract

We consider the inverse Seesaw scenario for neutrino masses with the approximate Lepton number symmetry broken dynamically by a scalar with Lepton number two. We show that the Majoron associated to the spontaneous symmetry breaking can alleviate the Hubble tension through its contribution to $\Delta N_\text{eff}$ and late decays to neutrinos. Among the additional fermionic states required for realizing the inverse Seesaw mechanism, sterile neutrinos at the keV-MeV scale can account for all the dark matter component of the Universe if produced via freeze-in from the decays of heavier degrees of freedom.