Physics Colloquium

Search for dark matter particle interactions in an extended nuclear recoil energy window with the LZ experiment

I will report on a search for high-energy nuclear recoils up to approximately 270keV from the LUX-ZEPLIN (LZ) experiment, operating at the Sanford Underground Research Facility in Lead, SD. In a 2.84 tonne-year exposure we find a single event consistent with a 248±23(stat)±23(sys) keV nuclear recoil in a region where background expectations are low. A profile likelihood ratio test disfavors the background-only hypothesis at 2.6σ global significance after accounting for the look-elsewhere effect, reaching a maximum local significance of 3.4σ across the models tested. The models that are consistent with the event come from effective field theories and inelastic dark matter scenarios. I will describe the design, operation, and performance of the LZ experiment, and walk through the analysis, including the event of interest and the rare backgrounds we characterized.

Join via Zoom: https://caltech.zoom.us/j/84497014003

Meeting ID: 844 9701 4003