The simplest case of dark inflaxion

TL;DR

This paper proposes a five-dimensional model called dark inflaxion, where an axion-like particle's Kaluza-Klein modes simultaneously explain cosmic inflation and dark matter, fitting observational data with a natural mass scale.

Contribution

It introduces a novel five-dimensional framework linking inflation and dark matter through Kaluza-Klein modes of an axion-like particle, unifying two major cosmological puzzles.

Findings

Model accommodates inflationary parameters and dark matter abundance simultaneously.

A simple mass scale choice yields observationally consistent results.

Potential for multifield inflation and dark matter scenarios within the model.

Abstract

Dark matter and cosmic inflation represent two of the major puzzles in cosmology. They are typically addressed by introducing separate fields with independent dynamics. On the other hand, extra dimensions might play an important role for observable physics. We introduce a five-dimensional model called dark inflaxion that includes an axion-like particle, whose Kaluza-Klein modes can describe inflation and dark matter. We show that a simple yet natural choice of the mass scale of the effective four-dimensional fields of our model can accommodate simultaneously the observable values of inflationary parameters and dark-matter abundance. It will be interesting to explore the consequences and predictions of more generic scenarios within the scope of our model, which include the possibility of multifield inflation and dark matter.