Hot New Early Dark Energy: Towards a Unified Dark Sector of Neutrinos, Dark Energy and Dark Matter

TL;DR

This paper proposes a unified dark sector model involving early dark energy, neutrino masses, and dark matter, which addresses the Hubble tension and makes testable predictions about neutrino mass bounds and dark sector properties.

Contribution

It introduces a novel scenario of hot early dark energy linked with neutrino mass generation and dark matter, with implications for cosmology and particle physics.

Findings

Strengthens bounds on the heaviest neutrino mass.

Provides two falsifiable predictions related to dark sector temperature.

Connects early dark energy with a larger gauge symmetry and dark matter origin.

Abstract

Hot new early dark energy describes a supercooled, first-order phase transition that takes place at sub-eV temperatures in the dark sector. It lowers the sound horizon, which provides a possible solution to the Hubble tension, and, at the same time, it can explain the neutrino masses through the inverse seesaw mechanism by making a set of sterile Majorana fermions massive. First, we argue that this scenario strengthens existing cosmological bounds on the heaviest neutrino mass. This, in turn, constrains the dark sector temperature, which provides us in total with two falsifiable predictions. In a second step, we discuss the phenomenological consequences of embedding hot new early dark energy in a larger gauge group that is partially broken above the TeV scale. This novel theory, which could even be motivated independently of the Hubble tension, completes the high-energy corner of the inverse seesaw mechanism and explains the mass of a dark matter candidate that can be produced through gravitational interactions at high energies.