Relic abundance of dark photon dark matter

Abstract

We present a new mechanism for producing the correct relic abundance of dark photon dark matter over a wide range of its mass, extending down to 10 −20 eV. The dark matter abundance is initially stored in an axion which is misaligned from its minimum. When the axion starts oscillating, it efficiently transfers its energy into dark photons via a tachyonic instability. If the dark photon mass is within a few orders of magnitude of the axion mass, m γ /ma = O(10 −3 − 1), then dark photons make up the dominant form of dark matter today. We present a numerical lattice simulation for a benchmark model that explicitly realizes our mechanism. This mechanism firms up the motivation for a number of experiments searching for dark photon dark matter.

Misalignment & Co.: (pseudo-)scalar and vector dark matter with curvature couplings

“…The situation of vectors is somewhat complicated by gauge invariance and the need to involve a Stueckelberg (or Higgs) mechanism. Constructing the appropriate Stueckelberg terms for the couplings to R leads to a naive violation of unitarity 2 already at relatively low energies [48]. A more detailed investigation, e.g.…”

On the wondrous stability of ALP dark matter

“…The authors of [44] argued that this effect could help deplete an excess of dark matter axions. This idea was further developped in [45], while [46,47] used the instability to generate dark photon dark matter 2 .…”

Co-interacting dark matter

“…It contains an ultralight vector DM, a dark photon A . Its relic abundance is achieved by non-thermal processes in the early universe, for instance, through inflationary quantum fluctuations [18], parametric resonances [47][48][49][50], and cosmic arXiv:1902.02348v3 [hep-ph] 16 Dec 2019 strings [51]. The other component is fermionic particles ψ, interacting with A via U (1) gauge coupling g ,…”