Speaker
Description
The LUX-ZEPLIN (LZ) experiment has searched for dark matter interactions that can produce nuclear recoils up to approximately 270 keVnr, including those described by non-relativistic effective field theory and inelastic dark matter models. Modeling the detector response across this broad energy range requires calibration of both nuclear- (NR) and electronic-recoil (ER) populations beyond the conventional WIMP search region. In LZ, these responses are described using the Noble Element Simulation Technique (NEST). High-energy neutron calibration data showed a discrepancy with a model that extrapolates the low-energy NR response beyond its calibration regime. An additional energy-dependent suppression of the charge yield was therefore incorporated into the NEST NR model. For electronic recoils, calibrations in the high-energy region also revealed an energy dependence in recombination fluctuations needed to reproduce the observed ER-band width. These developments were incorporated into NEST v2.4.5 and used in LZ's recent high-energy dark matter search. This talk will present the underlying calibration measurements, detector response modeling, and validation.