Dark Matter, Modified Gravity and the Mass of the Neutrino

TL;DR

This paper explores how certain modified gravity theories imply the existence of extra degrees of freedom that favor the presence of massive neutrinos, providing bounds on neutrino mass consistent with cosmological observations.

Contribution

It demonstrates that a subclass of covariant modified gravity theories predicts a preference for massive neutrinos and establishes a lower bound on neutrino mass in specific cosmological models.

Findings

Favours the presence of massive neutrinos in these theories

Provides a lower bound of 0.31 eV for neutrino mass in flat universe models with a cosmological constant

Suggests modified gravity theories can account for dark matter effects via neutrinos

Abstract

It has been suggested that Einstein's theory of General Relativity can be modified to accomodate mismatches between the gravitational field and luminous matter on a wide range of scales. Covariant theories of modified gravity generically predict the existence of extra degrees of freedom which may be interpreted as dark matter. We study a subclass of these theories where the overall energy density in these extra degrees of freedom is subdominant relative to the baryon density and show that they favour the presence of massive neutrinos. For some specific cases (such as a flat Universes with a cosmological constant) one finds a conservative lower bound on the neutrinos mass of $m_\nu>0.31$ eV.