Precision Cosmological Constraints on Atomic Dark Matter

Understand

Atomic dark matter is a simple but highly theoretically motivated possibility for an interacting dark sector that could constitute some or all of dark matter.

• We perform a comprehensive study of precision cosmological observables on minimal atomic dark matter, exploring for the first time the full parameter space of dark QED coupling and dark electron and proton masses $(\alpha_{D}, m_{e_{D}}, m_{p_{D}})$ as well as the two cosmological parameters of aDM mass fraction $f_{D}$ and temperature ratio $\xi$ at time of SM recombination.
• We also show how aDM can accommodate the $(H_0, S_8)$ tension from late-time measurements, leading to a better fit than $\Lambda$CDM or $\Lambda$CDM + dark radiation.
• Furthermore, including late-time measurements leads to closed contours of preferred $\xi$ and dark hydrogen binding energy.