Nuclear Atomic Dark Matter

Abstract

The matter coincidence, $Ω_{\rm DM}\simeq5Ω_b$, suggests a common origin for visible and dark matter (DM). We show that this motivates the study of nuclear atomic DM (naDM), which is composed of $\sim5\,\mathrm{GeV}$ mirror-neutron DM and a subdominant population of mirror elements. We realize naDM in the Mirror Twin Higgs, employing a twin Froggatt--Nielsen mechanism to generate fermion masses and realize spontaneous $\mathbb{Z}_2$ symmetry breaking. However, the low-energy mirror framework is more general and can emerge from other ultraviolet completions. naDM gives rise to a novel two-stage dark acoustic oscillation signature, multiple correlated direct-detection signals, and highly exotic twin astrophysics.