Background Determination for the LUX-ZEPLIN (LZ) Dark Matter Experiment

Abstract

The LUX-ZEPLIN experiment recently reported limits on WIMP-nucleus interactions from its initial science run, down to $9.2\times 10^{-48}$ cm${}^2$ for the spin-independent interaction of a 36 GeV/c${}^2$ WIMP at 90% confidence level. In this paper, we present a comprehensive analysis of the backgrounds important for this result and for other upcoming physics analyses, including neutrinoless double-beta decay searches and effective field theory interpretations of LUX-ZEPLIN data. We confirm that the in-situ determinations of bulk and fixed radioactive backgrounds are consistent with expectations from the ex-situ assays. The observed background rate after WIMP search criteria were applied was $(6.3\pm 0.5)\times 10^{-5}$ events/keV${}_{ee}$/kg/day in the low-energy region, approximately 60 times lower than the equivalent rate reported by the LUX experiment.

25 pages, 15 figures

References in corpus (12)

• Observation of Coherent Elastic Neutrino-Nucleus Scattering
• A new Generation of Standard Solar Models
• The LUX-ZEPLIN (LZ) Experiment
• First observation of two-neutrino double electron capture in ${}^{124}$Xe with XENON1T
• Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector
• ACTIVIA: Calculation of Isotope Production Cross-sections and Yields
• A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST
• Ultra-Low Energy Calibration of LUX Detector using ${}^{127}$Xe Electron Capture
• Double-Weak Decays of ${}^{124}$Xe and ${}^{136}$Xe in the XENON1T and XENONnT Experiments
• Measurement of Double Beta Decay Half-life of ${}^{136}$Xe with the PandaX-4T Detector
• Measurement of Charge and Light Yields for ${}^{127}$Xe L-Shell Electron Captures in Liquid Xenon
• Cosmogenic production of ${}^{37}$Ar in the context of the LUX-ZEPLIN experiment

Cited by in corpus (19)

• Dark Matter Search Results from 4.2 Tonne-Years of Exposure of the LUX-ZEPLIN (LZ) Experiment
• A search for new physics in low-energy electron recoils from the first LZ exposure
• New constraints on ultraheavy dark matter from the LZ experiment
• The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
• First Constraints on WIMP-Nucleon Effective Field Theory Couplings in an Extended Energy Region From LUX-ZEPLIN
• Energy-dependent Boosted Dark Matter from Diffuse Supernova Neutrino Background
• Mechanical detection of nuclear decays
• Measurement of ambient radon progeny decay rates and energy spectra in liquid argon using the MicroBooNE detector
• Neutrinoless Double Beta Decay Sensitivity of the XLZD Rare Event Observatory
• Two-neutrino double electron capture of ${}^{124}$Xe in the first LUX-ZEPLIN exposure
• New constraints on cosmic ray-boosted dark matter from the LUX-ZEPLIN experiment
• Attenuation of Cosmic Ray Electron Boosted Dark Matter
• The Design, Implementation, and Performance of the LZ Calibration Systems
• Probing the Scalar WIMP-Pion Coupling with the first LUX-ZEPLIN data
• Exploring the detection of AQNs in large liquid detectors
• Ultra-sensitive radon assay using an electrostatic chamber in a recirculating system
• Electron-ion recombination in composite interactions in liquid xenon
• Characterization of the Hamamatsu 8-inch R14688-100 PMT
• Search for New Physics via Low-Energy Electron Recoils with a 4.2 Tonne\times Year Exposure from the LZ Experiment