Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN
Year: 2026
Type: preprint
Abstract: The LUX-ZEPLIN experiment reported a candidate nuclear recoil at $248\,\mathrm{keV}$. This work proposes that endothermic self-scattering $χ_1+χ_1\toχ_2+χ_2$ in the Galaxy can produce an excited dark matter population, whose exothermic scattering $χ_2+\mathrm{Xe}\toχ_1+\mathrm{Xe}$ 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 $δ\gtrsim 500\,\mathrm{keV}$, the xenon recoil spectrum covers the candidate region and can yield an $\mathcal O(1)$ 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.
Source: arXiv (Cornell University)
Author: Xing, Chuan-Yang
Institution: China University of Petroleum, East China
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213518570