Physics Colloquium with Scott Kravitz

The identity of dark matter is one of the biggest open questions in fundamental physics. Through its gravitational interactions, we know that it makes up five times more of the matter in the Universe than the atomic matter we are familiar with, yet we know very little about its particle properties. Decades of experiments searching for direct evidence of dark matter particle interactions have so far failed to find anything conclusive. The LUX-ZEPLIN (LZ) dark matter experiment has been taking data with its 7-tonne dual-phase xenon time projection chamber a mile below the surface of the earth since 2021, and has recently released a search for high-energy interactions which finds a single event that appears inconsistent with known backgrounds at the level of 2.6 standard deviations. In this talk, I will present an overview of LZ’s dark matter search program, focusing on this recent analysis. I will discuss modeling of rare backgrounds, possible interpretations of this result, and prospects for a definitive explanation of this event of interest.