Taming the dark photon production via a non-minimal coupling to gravity

Abstract

Inflationary production of massive dark photons with non-minimal couplings to gravity shows surprising growth at large momenta. These couplings appear in the effective low energy description of a more fundamental theory. We find that the growth is absent in explicit gauge invariant UV-complete models. Such completions are also free of "ghost" instabilities, which often appear in the effective models.

Comments: 8 pages, 2 figures, accepted for publication in Physics Letters B