Addressing the Hubble tension with sterile neutrino dark matter

One of the promising dark matter (DM) candidates is a keV-scale sterile neutrino. In the early Universe, the observed relic of the sterile neutrino DM is generated via the Dodelson-Widrow mechanism. However, this production scenario is severely constrained by various astrophysical observations. Many nonstandard interactions between active (${\ensuremath{\nu}}_{a}$) and sterile (${\ensuremath{\nu}}_{s}$) neutrinos have been proposed to evade these astrophysical bounds. Here, we study sterile neutrinos in the context of a mass-varying scenario by coupling both active and sterile neutrinos to a scalar field. This novel mechanism opens up a new parameter space that generates the observed DM relic and addresses the Hubble tension. We find that the resulting parameter space can be fully probed by future x-ray missions.