Possible Couplings of Dark Matter

TL;DR

This paper explores various theoretical models of dark matter coupling to other fields, including non-minimal scalar-curvature coupling and connections to the inflaton, using astrophysical data to constrain parameters.

Contribution

It introduces a potentially more motivated approach via non-minimal coupling and links dark matter properties to inflationary parameters using observational constraints.

Findings

Upper bound on dark matter mass from astrophysical data

Constraints on unification and decoupling scales

Limits on the number of e-folds of inflation

Abstract

Dark matter interacts gravitationally, but it presumably interacts weakly through other channels, especially with respect to regular luminous matter. We look at different ways in which dark matter may couple to other fields. We briefly review some example approaches in the literature for modeling the coupling between dark energy and dark matter and examine the possibility of an arguably better-motivated approach via non-minimal coupling between a scalar field and the Ricci scalar, which is necessary for renormalization of the scalar field in curved space-time. We also show an example of a theory beyond the Standard Model in which dark matter is uniquely connected to the inflaton, and we use observational astrophysical constraints to specify an upper bound on the dark matter mass. In turn, this mass constraint implies a limit on the unification scale of the theory, a decoupling scale of the theory, and the number of $e$-folds of inflation allowed.