Interpreting the High-Recoil LUX-ZEPLIN Event with Bino-/Singlino-like and Higgsino Dark Matter
Abstract
The LUX-ZEPLIN (LZ) experiment has recently reported a nuclear-recoil candidate at ER≃248 keV. We study two supersymmetric interpretations based on distinct neutralino couplings to the Z boson. In the elastic case, a bino- or singlino-like neutralino scatters through a diagonal axial Z coupling set by the Higgsino asymmetry X=|N13|2−|N14|2 rather than by the total Higgsino fraction. Since the spin-dependent blind spot does not coincide with the spin-independent one, Higgs-mediated scattering can be suppressed while retaining X∼10−2. In the MSSM this favors low tanβ, in tension with the observed Higgs mass for a few-TeV squark spectrum, a tension relieved by the tree-level quartic of the NMSSM. An explicit NMSSM benchmark with mχ≃500 GeV and X≃0.007, below current LZ limits, obtains its relic abundance from a singlet-like pseudoscalar resonance just above threshold, which also suppresses present-day annihilation. In the inelastic case, a pseudo-Dirac Higgsino scatters endothermically, with a splitting of a few hundred keV generated by gauginos at the PeV scale which can be lowered by opposite-sign bino-wino cancellation, or by weak singlino mixing; the minimal thermal realization is strongly constrained by solar-neutrino searches. The two mechanisms predict distinct recoil spectra away from the candidate.
Related
- Sub-TeV Singlino Dark Matter in light from Sagittarius A∗ and LUX-ZEPLIN Nuclear-Recoil Event
- Higgsino Dark Matter Interpretation of the LUX-ZEPLIN 248 keV Nuclear-Recoil Event
- Higgsino dark matter compatible with the LUX-ZEPLIN high-energy nuclear-recoil event and IceCube constraints
- Higgsino dark matter in the Starobinsky supergravity with the MSSM in light of the LUX-ZEPLIN event
- Heavy Higgsino Dark Matter With Low Reheating in View of the LZ High-Recoil Event
BibTeX
@misc{roy2026interpreting,
title = {{Interpreting the High-Recoil LUX-ZEPLIN Event with Bino-/Singlino-like and Higgsino Dark Matter}},
author = {Subhojit Roy and Pedro Schwaller and Carlos E. M. Wagner},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.40234},
eprint = {2609.40234},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.40234},
note = {CC0},
}
RIS
TY - UNPB
TI - Interpreting the High-Recoil LUX-ZEPLIN Event with Bino-/Singlino-like and Higgsino Dark Matter
AU - Subhojit Roy
AU - Pedro Schwaller
AU - Carlos E. M. Wagner
PY - 2026
DA - 2026/09/30
PB - arXiv
DO - 10.48550/arxiv.2609.40234
UR - https://arxiv.org/abs/2609.40234
AB - The LUX-ZEPLIN (LZ) experiment has recently reported a nuclear-recoil candidate at E_R≃248 keV. We study two supersymmetric interpretations based on distinct neutralino couplings to the Z boson. In the elastic case, a bino- or singlino-like neutralino scatters through a diagonal axial Z coupling set by the Higgsino asymmetry X=|N_13|^2−|N_14|^2 rather than by the total Higgsino fraction. Since the spin-dependent blind spot does not coincide with the spin-independent one, Higgs-mediated scattering can be suppressed while retaining X∼10^−2. In the MSSM this favors low tanβ, in tension with the observed Higgs mass for a few-TeV squark spectrum, a tension relieved by the tree-level quartic of the NMSSM. An explicit NMSSM benchmark with m_χ≃500 GeV and X≃0.007, below current LZ limits, obtains its relic abundance from a singlet-like pseudoscalar resonance just above threshold, which also suppresses present-day annihilation. In the inelastic case, a pseudo-Dirac Higgsino scatters endothermically, with a splitting of a few hundred keV generated by gauginos at the PeV scale which can be lowered by opposite-sign bino-wino cancellation, or by weak singlino mixing; the minimal thermal realization is strongly constrained by solar-neutrino searches. The two mechanisms predict distinct recoil spectra away from the candidate.
ER -