PreprintCC0arXiv
Exothermic Dark Matter with a Dark Higgs: The LZ 248 keV Event and the Galactic Center Excess
Abstract
LUX-ZEPLIN (LZ) reported a 248 keV nuclear-recoil event. Exothermic dark matter can explain it in a dark U(1) model whose dark Higgs generates the dark photon mass and the mass splitting. A computed excited-state fraction gives two branches with dark photon masses near $1$ and 26 GeV for kinetic mixing ε=10−4. INTEGRAL/SPI limits on excited-state decays bound the LZ rate, and cosmic microwave background limits exclude the lighter branch at its likelihood minimum. For a dark Higgs boson near the dark photon mass, the heavier branch agrees with the southern-sky Galactic Center γ-ray excess.
Related
- Higgs-Portal Spin-1 Dark Matter with Parity-Violating Interaction for a Galactic Halo Gamma Ray Excess
- Comment on "Fermi-LAT Galactic Center Excess Morphology of Dark Matter in Simulations of the Milky Way Galaxy"
- A Simple Dark Matter Model to Explain the LZ Event and Galactic Center Excess
- Dark Matter Interpretations of the Galactic Center Gamma-Ray Excess with 18 Years of Fermi-LAT Data and the FL16Y Source Catalog
- Galactic Endothermic Production and Exothermic Detection of Excited Dark Matter: Implications for LUX-ZEPLIN
BibTeX
@misc{kim2026exothermic,
title = {{Exothermic Dark Matter with a Dark Higgs: The LZ 248 keV Event and the Galactic Center Excess}},
author = {Jinheung Kim and Jongkuk Kim and Pyungwon Ko},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.25423},
eprint = {2610.25423},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.25423},
note = {CC0},
}
RIS
TY - UNPB
TI - Exothermic Dark Matter with a Dark Higgs: The LZ 248 keV Event and the Galactic Center Excess
AU - Jinheung Kim
AU - Jongkuk Kim
AU - Pyungwon Ko
PY - 2026
DA - 2026/10/18
PB - arXiv
DO - 10.48550/arxiv.2610.25423
UR - https://arxiv.org/abs/2610.25423
AB - LUX-ZEPLIN (LZ) reported a 248 keV nuclear-recoil event. Exothermic dark matter can explain it in a dark U(1) model whose dark Higgs generates the dark photon mass and the mass splitting. A computed excited-state fraction gives two branches with dark photon masses near $1$ and 26 GeV for kinetic mixing ε=10^−4. INTEGRAL/SPI limits on excited-state decays bound the LZ rate, and cosmic microwave background limits exclude the lighter branch at its likelihood minimum. For a dark Higgs boson near the dark photon mass, the heavier branch agrees with the southern-sky Galactic Center γ-ray excess.
ER -