Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN
Abstract
The LUX-ZEPLIN experiment reported a candidate nuclear recoil at 248 keV. This work proposes that endothermic self-scattering χ1+χ1→χ2+χ2 in the Galaxy can produce an excited dark matter population, whose exothermic scattering χ2+Xe→χ1+Xe in xenon can account for the LZ candidate event. In a benchmark with a light scalar mediator, the conversion cross section is large enough for high-velocity Galactic dark matter particles to generate an excited fraction at the percent level. For dark matter masses near the TeV scale and mass splittings δ≳ 500 keV, the xenon recoil spectrum covers the candidate region and can yield an 𝒪(1) event count. The χ2 population produced in the Galaxy is colder than a relic population from the early Universe and yields a different nuclear recoil spectrum.
Related
- Exothermic and Endothermic Inelastic Dark Matter Interpretations at LZ: Sideband Constraints and Future Prospects
- Exothermic Dark Matter with a Dark Higgs: The LZ 248 keV Event and the Galactic Center Excess
- Early galactic heavy element production - a phenomenological approach
- Black Hole Spacetime Reconstruction from Galactic Rotation Curves: Thermodynamic Properties and Implications
- Sub-MeV gamma-ray lines from an endothermic interpretation of the LZ recoil candidate
BibTeX
@misc{xing2026galactic,
title = {{Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN}},
author = {Chuan-Yang Xing},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.17935},
eprint = {2609.17935},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17935},
}
RIS
TY - UNPB
TI - Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN
AU - Chuan-Yang Xing
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2609.17935
UR - https://arxiv.org/abs/2609.17935
AB - The LUX-ZEPLIN experiment reported a candidate nuclear recoil at 248 keV. This work proposes that endothermic self-scattering χ_1+χ_1→χ_2+χ_2 in the Galaxy can produce an excited dark matter population, whose exothermic scattering χ_2+Xe→χ_1+Xe in xenon can account for the LZ candidate event. In a benchmark with a light scalar mediator, the conversion cross section is large enough for high-velocity Galactic dark matter particles to generate an excited fraction at the percent level. For dark matter masses near the TeV scale and mass splittings δ≳ 500 keV, the xenon recoil spectrum covers the candidate region and can yield an 𝒪(1) event count. The χ_2 population produced in the Galaxy is colder than a relic population from the early Universe and yields a different nuclear recoil spectrum.
ER -