LZ Nuclear-Recoil Excess from Boosted Light Magnetic Dipole-dipole Dark Matter
Abstract
The LZ collaboration has reported a nuclear-recoil excess near 248 keV with a global significance of 2.6σ. Although halo dark matter with a magnetic dipole-dipole interaction and a TeV-scale mass provides the best fit to the excess among the interactions considered by LZ, it predicts a considerable number of events at lower recoil energies, where no excess is observed. We show that a boosted velocity distribution can alleviate this tension and provide a better fit to the LZ recoil spectrum. Moreover, the boost opens up the possibility of explaining the excess with much lighter dark matter, with masses down to the GeV scale. We demonstrate these features first in a model-independent analysis and then realize them in a concrete dark matter model, in which halo dark matter annihilates into on-shell mediators that subsequently decay into boosted dark-sector particles. Our results demonstrate that boosted dark sector particles provide a viable interpretation of the LZ excess.
Related
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- Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess
- Neutron disappearance and the LZ nuclear recoil event
- Nuclear recoil effects with a realistic nuclear charge form factor
BibTeX
@misc{liang2026nuclearrecoil,
title = {{LZ Nuclear-Recoil Excess from Boosted Light Magnetic Dipole-dipole Dark Matter}},
author = {Jin-Han Liang and Zuowei Liu and Van Que Tran and Yongheng Xu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.06756},
eprint = {2609.06756},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06756},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - LZ Nuclear-Recoil Excess from Boosted Light Magnetic Dipole-dipole Dark Matter
AU - Jin-Han Liang
AU - Zuowei Liu
AU - Van Que Tran
AU - Yongheng Xu
PY - 2026
DA - 2026/09/06
PB - arXiv
DO - 10.48550/arxiv.2609.06756
UR - https://arxiv.org/abs/2609.06756
AB - The LZ collaboration has reported a nuclear-recoil excess near 248 keV with a global significance of 2.6σ. Although halo dark matter with a magnetic dipole-dipole interaction and a TeV-scale mass provides the best fit to the excess among the interactions considered by LZ, it predicts a considerable number of events at lower recoil energies, where no excess is observed. We show that a boosted velocity distribution can alleviate this tension and provide a better fit to the LZ recoil spectrum. Moreover, the boost opens up the possibility of explaining the excess with much lighter dark matter, with masses down to the GeV scale. We demonstrate these features first in a model-independent analysis and then realize them in a concrete dark matter model, in which halo dark matter annihilates into on-shell mediators that subsequently decay into boosted dark-sector particles. Our results demonstrate that boosted dark sector particles provide a viable interpretation of the LZ excess.
ER -