Inelastic Singlet-Doublet Fermion Dark Matter in light of the 248 keV LZ event
Abstract
Recently, the LUX-ZEPLIN (LZ) collaboration reported the observation of a single dark matter (DM)-nucleus scattering event at a nuclear recoil energy of 248±23stat±23sys keV, corresponding to an exposure of 2.84 tonne-year. The absence of events at lower nuclear recoil energies in the predicted spectrum is naturally explained if the underlying process is inelastic DM-nucleus scattering. Motivated by this, we investigate the singlet-doublet fermion DM model, in which the DM consists of two pseudo-Dirac states: the Majorana nature of the lighter state forbids tree level Z-mediated elastic scattering identically, while the same states enable inelastic DM-nucleus scattering via Z exchange, with any residual elastic scattering proceeding only through a suppressed Higgs-mediated channel. We further extend the model with a Z2-even scalar triplet, which is responsible both for generating the pseudo-Dirac splitting and for realizing Majorana neutrino masses via the Type-II seesaw mechanism.
Related
- LZ nuclear recoil event from inelastic singlet-doublet scalar dark matter
- Two-Component Dark Matter and Strongly First-Order Electroweak Phase Transition via a Two-Step Mechanism in the Inert Doublet plus Real Singlet Model
- Singlet-doublet dark matter induced radiative neutrino mass and TeV scale leptogenesis
- 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
BibTeX
@misc{borah2026inelastic,
title = {{Inelastic Singlet-Doublet Fermion Dark Matter in light of the 248 keV LZ event}},
author = {Debasish Borah and Sujit Kumar Sahoo and Narendra Sahu and Shashwat Sharma},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07800},
eprint = {2609.07800},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07800},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Inelastic Singlet-Doublet Fermion Dark Matter in light of the 248 keV LZ event
AU - Debasish Borah
AU - Sujit Kumar Sahoo
AU - Narendra Sahu
AU - Shashwat Sharma
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07800
UR - https://arxiv.org/abs/2609.07800
AB - Recently, the LUX-ZEPLIN (LZ) collaboration reported the observation of a single dark matter (DM)-nucleus scattering event at a nuclear recoil energy of 248±23_stat±23_sys keV, corresponding to an exposure of 2.84 tonne-year. The absence of events at lower nuclear recoil energies in the predicted spectrum is naturally explained if the underlying process is inelastic DM-nucleus scattering. Motivated by this, we investigate the singlet-doublet fermion DM model, in which the DM consists of two pseudo-Dirac states: the Majorana nature of the lighter state forbids tree level Z-mediated elastic scattering identically, while the same states enable inelastic DM-nucleus scattering via Z exchange, with any residual elastic scattering proceeding only through a suppressed Higgs-mediated channel. We further extend the model with a Z_2-even scalar triplet, which is responsible both for generating the pseudo-Dirac splitting and for realizing Majorana neutrino masses via the Type-II seesaw mechanism.
ER -