Snowmass2021 Cosmic Frontier White Paper: Dark Matter Physics from Halo Measurements

Understand

The non-linear process of cosmic structure formation produces gravitationally bound overdensities of dark matter known as halos.

• The abundances, density profiles, ellipticities, and spins of these halos can be tied to the underlying fundamental particle physics that governs dark matter at microscopic scales.
• Thus, macroscopic measurements of dark matter halos offer a unique opportunity to determine the underlying properties of dark matter across the vast landscape of dark matter theories.
• This white paper summarizes the ongoing rapid development of theoretical and experimental methods, as well as new opportunities, to use dark matter halo measurements as a pillar of dark matter physics.