Dark matter makes up 85% of the matter in our Universe, but we have yet to learn its identity. A broad array of search strategies are needed to probe for non-gravitational interactions between dark matter and ordinary matter. While most searches focus on Weakly Interacting Massive Particles (WIMPs) with masses above 1 GeV/c^2, it is imperative to also consider other motivated dark matter candidates. In this talk, I will discuss dark matter with masses between 1 MeV/c^2 and 1 GeV/c^2, which is a theoretically and phenomenologically appealing possibility and presents a new frontier in the search for dark matter. I will describe novel dark matter direct-detection strategies that can probe this under-explored mass range, focusing on searches for dark matter particles that scatter off electrons in noble-liquid, scintillating, and semiconductor targets. In particular, I will highlight SENSEI, a funded experiment that will use new ultra-low-threshold silicon CCD detectors (“Skipper CCDs”). I will describe some first results from SENSEI and show how this experiment will probe vast new regions of unexplored dark-matter parameter space in the next few years.
Host: Reina Maruyama
Tea after the talk in SPL 3rd Floor Lounge