A closer look at the LZ 248 keV event through the lens of cosmic-ray boosted dark matter
Abstract
We investigate whether cosmic ray boosted dark matter (CRDM) can explain the 248 keV nuclear recoil event observed by the LUX-ZEPLIN (LZ) collaboration. We consider spin-dependent interactions, mediated by a pseudoscalar, and incorporate relativistic kinematics in CRDM production, propagation, and detection. We find that spin-dependent interactions can produce sufficient number of nuclear recoils in the observed region of interest, without populating events at lower energies, which have not been observed. However, for a benchmark pseudoscalar interaction corresponding to the non-relativistic effective operator 𝕆6, the coupling required to produce the observed event corresponds to an energy scale comparable to the momentum transfer scales, thus making contact interaction approach challenging. Instead, we find that a pseudoscalar mediator with mass ∼ 300MeV and O(1) couplings can provide a promising solution to this unexplained event.
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BibTeX
@misc{chauhan2026closer,
title = {{A closer look at the LZ 248 keV event through the lens of cosmic-ray boosted dark matter}},
author = {Bhavesh Chauhan and Soham Sahasrabuddhe and Manibrata Sen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.24982},
eprint = {2609.24982},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24982},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A closer look at the LZ 248 keV event through the lens of cosmic-ray boosted dark matter
AU - Bhavesh Chauhan
AU - Soham Sahasrabuddhe
AU - Manibrata Sen
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.24982
UR - https://arxiv.org/abs/2609.24982
AB - We investigate whether cosmic ray boosted dark matter (CRDM) can explain the 248 keV nuclear recoil event observed by the LUX-ZEPLIN (LZ) collaboration. We consider spin-dependent interactions, mediated by a pseudoscalar, and incorporate relativistic kinematics in CRDM production, propagation, and detection. We find that spin-dependent interactions can produce sufficient number of nuclear recoils in the observed region of interest, without populating events at lower energies, which have not been observed. However, for a benchmark pseudoscalar interaction corresponding to the non-relativistic effective operator 𝕆_6, the coupling required to produce the observed event corresponds to an energy scale comparable to the momentum transfer scales, thus making contact interaction approach challenging. Instead, we find that a pseudoscalar mediator with mass ∼ 300MeV and O(1) couplings can provide a promising solution to this unexplained event.
ER -