A Dark-Dimension Origin of Geometric Inelastic Dark Matter: The LUX-ZEPLIN High-Recoil Event and Multi-Target Tests
Abstract
The extended nuclear-recoil analysis of LUX-ZEPLIN (LZ) has reported one event compatible with a recoil energy near $248$ keV, motivating endothermic dark-matter scenarios with support at large recoil energy. We study a pseudo-Dirac electroweak-doublet dark-matter model embedded in a five-dimensional Dark-Dimension framework. The Standard Model and the vectorlike electroweak doublets are localized on the visible brane, while dark-number violation is communicated through a neutral bulk state. The resulting mass splitting is exponentially suppressed, δ=δUVe−2πMR, providing a geometric origin for the few-hundred-keV scale relevant to inelastic scattering. The neutral weak current is dominantly off diagonal, fixing the neutron-scale normalization at σχnZ≃1.86×10−39 cm2. Using a two-bin Poisson diagnostic of the extended LZ recoil window, we find a shallow minimum near (mχ,δ)≃(1.35 TeV,366 keV), while the thermally motivated point (1.1 TeV,360 keV) lies only Δχ2≃0.21 higher. The same benchmark is kinematically inaccessible to light targets but remains open for xenon and tungsten, providing a characteristic multi-target test of the model. For CaWO4 we obtain an integrated tungsten rate of 3.15×10−2 events kg−1 yr−1 in the $95−−150$ keV interval. These results connect the geometric origin of the pseudo-Dirac splitting with high-recoil direct-detection phenomenology.
Related
- A Peccei-Quinn Origin for Inelastic Electroweak Dark Matter after LUX-ZEPLIN
- Inelastic Dark Matter from a Higher-Dimensional Operator: The LUX-ZEPLIN High-Recoil Event and Thermal Relic
- Inelastic B−L scalar dark matter and the LUX-ZEPLIN event
- Solar Neutrino Constraints on Inelastic Dark Matter Scattering in Light of Recent LUX-ZEPLIN Observations
- Inelastic Dark Matter Signature at High Recoil Energy in LUX-ZEPLIN and CRESST
BibTeX
@misc{ahmed2026darkdimension,
title = {{A Dark-Dimension Origin of Geometric Inelastic Dark Matter: The LUX-ZEPLIN High-Recoil Event and Multi-Target Tests}},
author = {Waqas Ahmed and George K. Leontaris},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07138},
eprint = {2609.07138},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07138},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - A Dark-Dimension Origin of Geometric Inelastic Dark Matter: The LUX-ZEPLIN High-Recoil Event and Multi-Target Tests
AU - Waqas Ahmed
AU - George K. Leontaris
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07138
UR - https://arxiv.org/abs/2609.07138
AB - The extended nuclear-recoil analysis of LUX-ZEPLIN (LZ) has reported one event compatible with a recoil energy near $248$ keV, motivating endothermic dark-matter scenarios with support at large recoil energy. We study a pseudo-Dirac electroweak-doublet dark-matter model embedded in a five-dimensional Dark-Dimension framework. The Standard Model and the vectorlike electroweak doublets are localized on the visible brane, while dark-number violation is communicated through a neutral bulk state. The resulting mass splitting is exponentially suppressed, δ=δ_UVe^−2πMR, providing a geometric origin for the few-hundred-keV scale relevant to inelastic scattering. The neutral weak current is dominantly off diagonal, fixing the neutron-scale normalization at σ_χn^Z≃1.86×10^−39 cm^2. Using a two-bin Poisson diagnostic of the extended LZ recoil window, we find a shallow minimum near (m_χ,δ)≃(1.35 TeV,366 keV), while the thermally motivated point (1.1 TeV,360 keV) lies only Δχ^2≃0.21 higher. The same benchmark is kinematically inaccessible to light targets but remains open for xenon and tungsten, providing a characteristic multi-target test of the model. For CaWO_4 we obtain an integrated tungsten rate of 3.15×10^−2 events kg^−1 yr^−1 in the $95−−150$ keV interval. These results connect the geometric origin of the pseudo-Dirac splitting with high-recoil direct-detection phenomenology.
ER -