High-Energy Nuclear Recoils from Boosted Dark Matter for the LZ 248-keV Event: Beyond the Halo-Dependent High-Velocity Tail
4 affiliations
- 1Department of Physical Sciences , Jazan University , Jazan 45142 , Saudi Arabia
- 2Department of Physics , University of South Dakota , Vermillion , SD 57069 , USA
- 3Department of Physics and Astronomy , University of Kansas , Lawrence , KS 66045 , USA
- 4Department of Physics and Institute for Sciences of the Universe , Chungnam National University , Daejeon 34134 , Korea
Abstract
The LUX-ZEPLIN (LZ) Collaboration has reported a nuclear-recoil candidate at ER=248±23stat±23sys keV, with a maximum local significance of 3.4σ and a global significance of 2.6σ. A prominent interpretation invokes heavy halo dark matter near an inelastic threshold and therefore depends sensitively on the poorly constrained high-speed tail of the Galactic velocity distribution. In this Letter, we propose a qualitatively different possibility based on light boosted dark matter (BDM), whose incident energy is determined primarily by the dark-sector mass spectrum. We consider multi-component scenarios in which the boosted state scatters elastically or inelastically off xenon nuclei. For elastic scattering, pseudoscalar-mediated momentum dependence suppresses low-energy recoils. Near-threshold endothermic scattering of a nearly monochromatic BDM flux can instead confine the signal between kinematically determined recoil endpoints, suppressing events in both the low- and high-energy sidebands. The upscattered state may furthermore decay invisibly within the dark sector, preserving a single-nuclear-recoil signature without requiring it to be detector-stable. We present representative benchmark spectra and discuss complementary tests using other target nuclei and large-volume liquid-scintillator experiments.
Related
- Exothermic nuclear recoils from thermal quasi-pNGB dark matter
- Super-Lindhard Ionization from 254 eVnr Nuclear Recoils in Germanium
- Can Nuclear Recoils and Solar Neutrinos Resolve the Composition of Singlino-Higgsino Dark Matter?
- Nuclear Recoils from Invisible Neutron-Pair Annihilation and the LZ event
- Light and charge yields from nuclear recoils in noble liquids: From sub-keV energies to 1 MeV
BibTeX
@misc{alhazmi2026highenergy,
title = {{High-Energy Nuclear Recoils from Boosted Dark Matter for the LZ 248-keV Event: Beyond the Halo-Dependent High-Velocity Tail}},
author = {Haider Alhazmi and Doojin Kim and Kyoungchul Kong and Jong-Chul Park and Seodong Shin},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.06890},
eprint = {2609.06890},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06890},
note = {CC0},
}
RIS
TY - UNPB
TI - High-Energy Nuclear Recoils from Boosted Dark Matter for the LZ 248-keV Event: Beyond the Halo-Dependent High-Velocity Tail
AU - Haider Alhazmi
AU - Doojin Kim
AU - Kyoungchul Kong
AU - Jong-Chul Park
AU - Seodong Shin
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.06890
UR - https://arxiv.org/abs/2609.06890
AB - The LUX-ZEPLIN (LZ) Collaboration has reported a nuclear-recoil candidate at E_R=248±23_stat±23_sys keV, with a maximum local significance of 3.4σ and a global significance of 2.6σ. A prominent interpretation invokes heavy halo dark matter near an inelastic threshold and therefore depends sensitively on the poorly constrained high-speed tail of the Galactic velocity distribution. In this Letter, we propose a qualitatively different possibility based on light boosted dark matter (BDM), whose incident energy is determined primarily by the dark-sector mass spectrum. We consider multi-component scenarios in which the boosted state scatters elastically or inelastically off xenon nuclei. For elastic scattering, pseudoscalar-mediated momentum dependence suppresses low-energy recoils. Near-threshold endothermic scattering of a nearly monochromatic BDM flux can instead confine the signal between kinematically determined recoil endpoints, suppressing events in both the low- and high-energy sidebands. The upscattered state may furthermore decay invisibly within the dark sector, preserving a single-nuclear-recoil signature without requiring it to be detector-stable. We present representative benchmark spectra and discuss complementary tests using other target nuclei and large-volume liquid-scintillator experiments.
SN - 2331-8422
ER -