PreprintCC BY 4.0arXiv
A Freeze-In Interpretation of the LZ High-Energy Nuclear Recoil Event
Abstract
The recent LUX-ZEPLIN (LZ) experiment analysis reported a high energy nuclear recoil candidate at ER ≃ 248 keV, motivating interpretations in terms of inelastic dark matter. We study this event in a pseudo-Dirac fermion model with a vector boson mediator Z', assuming a low-reheating temperature and dark matter production through freeze-in at stronger coupling. In contrast to the thermal freeze-out case, the reheating temperature provides an additional parameter controlling the relic abundance and breaks the one-to-one relation between the dark matter mass and direct-detection cross section. As a result, the LZ candidate can be reproduced over a continuous region of parameter space, including mass splitting below the thermal benchmark.
Related
- Higgsino Dark Matter Interpretation of the LUX-ZEPLIN 248 keV Nuclear-Recoil Event
- A Vector-Like Lepton Interpretation of the High-Energy Nuclear Recoil Candidate in LUX-ZEPLIN
- A Comprehensive Interpretation of the LZ High-Energy Recoil Event: A Minimal U(1)B Dark Sector and Its Experimental Tests
- Higgsino dark matter compatible with the LUX-ZEPLIN high-energy nuclear-recoil event and IceCube constraints
- TeV Higgsino Interpretation of the LZ High-Recoil Event with Intermediate-Scale Electroweak Gauginos
BibTeX
@misc{caboalmeida2026freezein,
title = {{A Freeze-In Interpretation of the LZ High-Energy Nuclear Recoil Event}},
author = {D. Cabo-Almeida and F. Costa and D. Feiteira and V. Oliveira},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.13130},
eprint = {2609.13130},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.13130},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Freeze-In Interpretation of the LZ High-Energy Nuclear Recoil Event
AU - D. Cabo-Almeida
AU - F. Costa
AU - D. Feiteira
AU - V. Oliveira
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2609.13130
UR - https://arxiv.org/abs/2609.13130
AB - The recent LUX-ZEPLIN (LZ) experiment analysis reported a high energy nuclear recoil candidate at E_R ≃ 248 keV, motivating interpretations in terms of inelastic dark matter. We study this event in a pseudo-Dirac fermion model with a vector boson mediator Z', assuming a low-reheating temperature and dark matter production through freeze-in at stronger coupling. In contrast to the thermal freeze-out case, the reheating temperature provides an additional parameter controlling the relic abundance and breaks the one-to-one relation between the dark matter mass and direct-detection cross section. As a result, the LZ candidate can be reproduced over a continuous region of parameter space, including mass splitting below the thermal benchmark.
ER -