Exothermic Dark Matter at LZ
- 1PITT PACC , Department of Physics and Astronomy , University of Pittsburgh , 3941 O'Hara St. , Pittsburgh , PA 15260 , USA
Abstract
We investigate whether the high-energy nuclear recoil reported by the LUX-ZEPLIN (LZ) experiment can be explained by exothermic dark matter. We realize this framework in a minimal inelastic dark photon model and show that both freeze-out and low-reheating-temperature freeze-in cosmologies can reproduce the observed rate, with GeV-scale mediator masses and small kinetic mixing. We find that the LZ event can occur in a preferred parameter region with dark matter mass around mχ∼ 30−200 GeV, and mass splitting δ∼ 0.5−1 MeV. The scenario is largely insensitive to halo uncertainties and has robust predictions for different targets. In particular, argon and germanium detectors are expected to observe events at energies above the current xenon window.
Related
- Exothermic Dark Matter with a Dark Higgs: The LZ 248 keV Event and the Galactic Center Excess
- Exothermic nuclear recoils from thermal quasi-pNGB dark matter
- Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN
- Decaying Dark Matter for the Exothermic Recoil at LZ
- Exothermic and Endothermic Inelastic Dark Matter Interpretations at LZ: Sideband Constraints and Future Prospects
BibTeX
@misc{lima2026exothermic,
title = {{Exothermic Dark Matter at LZ}},
author = {Carlos Henrique de Lima},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.05204},
eprint = {2609.05204},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.05204},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Exothermic Dark Matter at LZ
AU - Carlos Henrique de Lima
PY - 2026
DA - 2026/09/04
PB - arXiv
DO - 10.48550/arxiv.2609.05204
UR - https://arxiv.org/abs/2609.05204
AB - We investigate whether the high-energy nuclear recoil reported by the LUX-ZEPLIN (LZ) experiment can be explained by exothermic dark matter. We realize this framework in a minimal inelastic dark photon model and show that both freeze-out and low-reheating-temperature freeze-in cosmologies can reproduce the observed rate, with GeV-scale mediator masses and small kinetic mixing. We find that the LZ event can occur in a preferred parameter region with dark matter mass around m_χ∼ 30−200 GeV, and mass splitting δ∼ 0.5−1 MeV. The scenario is largely insensitive to halo uncertainties and has robust predictions for different targets. In particular, argon and germanium detectors are expected to observe events at energies above the current xenon window.
SN - 2331-8422
ER -