Dark matter makes up 85% of the matter in our Universe, but we have yet to learn its identity. While most experimental searches focus on Weakly Interacting Massive Particles (WIMPs) with masses above the proton (about 1 GeV/c^2), many natural dark-matter candidates have masses below the proton and are invisible in traditional WIMP searches. In this talk, I will discuss the search for dark matter with masses between about 500 keV/c^2 to 1 GeV/c^2 (“sub-GeV dark matter”), which has seen tremendous progress in the last few years. I will describe several direct-detection strategies, and discuss how to search for dark matter interactions with electrons and nuclei in various target materials, such as noble liquids and semiconductors. I will in particular highlight SENSEI, a funded experiment that will use ultra-low-threshold silicon CCD detectors (“Skipper CCDs”) capable of detecting even single electrons. I will describe the latest results from SENSEI, and how SENSEI and other experiments expect to probe orders of magnitude of novel dark matter parameter space in the next few years.
Zoom link: https://bnl.zoomgov.com/j/1605020278?pwd=cHJ1bDRuK1FDNnZLSnpxVkZhcDQ3QT09