Dark matter self-interactions and small scale structure

Speaker: Sean Tulin

Astrophysical observations of the structure of galaxies and clusters are no longer simply proving the existence of dark matter (DM), but have sharpened into a tool probing the particle physics of DM. I review small scale structure anomalies for cold DM and their possible implications for DM physics, such as the existence of forces in the dark sector. New results on cluster scales provide a new important handle for constraining DM's interactions, its mass, and the mass of dark mediator particles. I discuss how self-interactions arise in particle physics models and are complementarity with other types of dark matter searches.