Kaluza--Klein Dark-Photon Mediation of Inelastic Dark Matter at LUX-ZEPLIN
Abstract
We study a five-dimensional realization of endothermic dark matter motivated by the recent high-recoil LUX-ZEPLIN event. A pseudo-Dirac Standard-Model singlet fermion is localized in the extra dimension and couples to a bulk U(1)D gauge field. The same localization that suppresses a distant-brane Majorana operator and generates the inelastic splitting also controls the couplings to the Kaluza--Klein (KK) dark-photon tower, producing a localization-filtered mediator propagator. We organize the phenomenology around two representative mass--splitting points: an LZ benchmark, mχ=1.10 TeV and δ=365 keV, and an IceCube-motivated comparison point, mχ=1.08 TeV and δ=566 keV. The latter is used only to compare terrestrial and solar kinematics; the published IceCube bound is Higgsino-specific and is not directly imposed on our singlet KK model. At the LZ benchmark with R−1=0.30 GeV and m0=0.10 GeV, the KK tower enhances the high-recoil xenon rate by a factor of about four relative to a single dark photon at fixed microscopic coupling. The LZ point lies just below the terrestrial halo speed ceiling, whereas the 566 keV comparison point is inaccessible to ordinary xenon scattering and instead lies in a kinematic regime accessible to solar capture; any neutrino constraint on the present singlet model remains dependent on its capture and annihilation dynamics. The characteristic prediction of the extra-dimensional construction is therefore a correlated interplay of localization, KK spectral distortion, and inelastic kinematics.
Related
- Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess
- Solar Neutrino Constraints on Inelastic Dark Matter Scattering in Light of Recent LUX-ZEPLIN Observations
- Inelastic dark matter and baryon flavor symmetry in light of LUX-ZEPLIN (LZ) experiment
- Inelastic Self-interacting Dark Matter and LUX-ZEPLIN 248 keV Event in a Dirac Modular Inverse Seesaw
- Higgsino dark matter in the Starobinsky supergravity with the MSSM in light of the LUX-ZEPLIN event
BibTeX
@misc{ahmed2026kaluzaklein,
title = {{Kaluza--Klein Dark-Photon Mediation of Inelastic Dark Matter at LUX-ZEPLIN}},
author = {Waqas Ahmed and George K. Leontaris},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22739},
eprint = {2609.22739},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22739},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Kaluza--Klein Dark-Photon Mediation of Inelastic Dark Matter at LUX-ZEPLIN
AU - Waqas Ahmed
AU - George K. Leontaris
PY - 2026
DA - 2026/09/19
PB - arXiv
DO - 10.48550/arxiv.2609.22739
UR - https://arxiv.org/abs/2609.22739
AB - We study a five-dimensional realization of endothermic dark matter motivated by the recent high-recoil LUX-ZEPLIN event. A pseudo-Dirac Standard-Model singlet fermion is localized in the extra dimension and couples to a bulk U(1)_D gauge field. The same localization that suppresses a distant-brane Majorana operator and generates the inelastic splitting also controls the couplings to the Kaluza--Klein (KK) dark-photon tower, producing a localization-filtered mediator propagator. We organize the phenomenology around two representative mass--splitting points: an LZ benchmark, m_χ=1.10 TeV and δ=365 keV, and an IceCube-motivated comparison point, m_χ=1.08 TeV and δ=566 keV. The latter is used only to compare terrestrial and solar kinematics; the published IceCube bound is Higgsino-specific and is not directly imposed on our singlet KK model. At the LZ benchmark with R^−1=0.30 GeV and m_0=0.10 GeV, the KK tower enhances the high-recoil xenon rate by a factor of about four relative to a single dark photon at fixed microscopic coupling. The LZ point lies just below the terrestrial halo speed ceiling, whereas the 566 keV comparison point is inaccessible to ordinary xenon scattering and instead lies in a kinematic regime accessible to solar capture; any neutrino constraint on the present singlet model remains dependent on its capture and annihilation dynamics. The characteristic prediction of the extra-dimensional construction is therefore a correlated interplay of localization, KK spectral distortion, and inelastic kinematics.
ER -