Session J2: Invited Session: Dark Matter - Beyond WIMPs

keV-mass dark matter candidates and constraints

The cold dark matter cosmological model has been extremely successful in explaining cosmic structure on large scales, but has ongoing challenges from observations that probe small-scale structures. Warm dark matter (WDM) provides a compelling alternative that help resolve such issues whilst maintaing the successes on large scales. After overviewing motivations for going beyond WIMP-based dark matter, I will review candidates of keV-mass WDM particles and their production mechanisms in the early Universe. I will then discuss their cosmological implications and explore the variety of constraints coming from structure as well as X-ray observations.   

Exploring the Dark Sector

Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This talk summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. It discusses axions, axion-like particles, dark photons, and other dark-sector particles, including sub-GeV dark matter. In many cases, the exploration of dark sectors can proceed with existing facilities and comparatively modest experiments. A rich, diverse, and low-cost experimental program has the potential for one or more game-changing discoveries.