Who ordered that? An anomalous event in the LUX-ZEPLIN dark matter search

The LUX-ZEPLIN experiment (LZ) employs the world’s most sensitive detector looking for dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Seven tonnes of ultra-pure liquid xenon (LXe) are instrumented to detect scintillation and ionization signals from incoming particles, along with two veto detectors to tag background signals. Though typical WIMP searches focus on low-energy interactions of O(10 keV), there are viable, generic models in which these low-energy scatters are suppressed, leaving higher energy O(>=100 keV) recoils as the dominant signal from a WIMP scatter. Additionally, background rates are greatly reduced at these high energies. Analyzing 220 live days of data, we observe one event that is consistent with a 250 keV nuclear recoil, in significant tension with our background models. I will discuss these recent results, what we have learned so far, and what we plan to do going forward.

Speaker: Aaron Manalaysay, Physicist Project Sci/Engr, Lawrence Berkeley Laboratory

Editor's Note: The speaker originally scheduled today was to give his talk on August 31, 2026 instead.