Who ordered the ~250 keV nuclear recoil observed by LZ??
- Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars
September 22, 2026 2:00 PM
PAIS 3205
- Presenter:
- Rouzbeh Allahverdi & Dinesh Loomba
The LUX-ZEPLIN (LZ) experiment has recently reported on a search for dark matter (DM) particles interacting with xenon nuclei in an exposure of 2.84 tonne-years. They have observed one event with characteristics consistent with a nuclear recoil of 248 ± 23 (stat) ± 23 (sys) keV, in a region where the known background expectation is low. Assuming that this event is a DM candidate, the absence of lower nuclear recoil events is naturally explained by inelastically scattering DM. The observed rate and spectra are consistent with a thermal 1.1 TeV Higgsino DM with a mass splitting ∼ 370 − 490 keV between the two lowest-lying Majorana states. However, non-observation of high energy neutrinos from DM annihilation in the Sun seems to exclude this interpretation of the recent LZ event. The solar limit can be evaded by a non-thermal lower mass Higgsino DM, or other models of inelastic DM.
