Solar Capture Tests of Inelastic Dark Matter after the LZ High-Recoil Event
- 1Department of Physics , James-Franck-Str. 1 , 85748 Garching , Germany
- 2Technical University of Munich , TUM School of Natural Sciences ,
Abstract
The LUX-ZEPLIN (LZ) Collaboration has reported a $248$ keV nuclear-recoil candidate for which endothermic dark matter (DM) gives some of the largest local significances. We study Solar-capture constraints on three interpretations: a thermal Higgsino, a thermal pseudo-Dirac fermion with off-diagonal vector interactions, and neutron-philic endothermic spin-dependent scattering through 𝒪4. The canonical full-density thermal Higgsino is excluded: its LZ-preferred splitting near 0.38 MeV lies well below the splitting required to suppress Solar capture sufficiently to satisfy the IceCube upper limits on DM annihilation in the Sun, δ≳0.51-0.56 MeV. For the pseudo-Dirac benchmark parameters that fit the LZ event, we find C⊙=1.53×1020 s−1, while two-state kinetics limits the fixed-orbit annihilation rate to ΓA≲4.4×1014 s−1, about 1.7×105 below the IceCube upper limit for the bb̅ channel. A semi-analytic treatment indicates that re-excitation cycles further cool the captured population, although a full phase-space calculation is required for its final distribution. For neutron-philic 𝒪4 scattering at mχ=1 TeV and δ=300 keV, finite-temperature capture gives C⊙=3.98×1017 s−1, with nuclear-structure uncertainties giving an envelope (1.77-9.72)×1017 s−1. Under the equilibrium assumption, the upper edge remains about a factor $154$ below the IceCube upper limit for the bb̅ channel. We use bb̅ only as a soft-hadronic proxy because an exact constraint requires the model-specific annihilation spectrum. Solar capture therefore excludes the thermal-Higgsino interpretation but not endothermic explanations generically.
Related
- LZ nuclear recoil event from inelastic singlet-doublet scalar dark matter
- Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess
- Implications of Inelastic Dark Matter for Primordial Dark-Star Evolution: Kinematic Thresholds and Nonthermal Capture
- Solar Neutrino Constraints on Inelastic Dark Matter Scattering in Light of Recent LUX-ZEPLIN Observations
- Testing Higgs-Coupled Minimal Dark Matter with Solar Neutrinos after the LZ High-Recoil Event
BibTeX
@misc{mauro2026solar,
title = {{Solar Capture Tests of Inelastic Dark Matter after the LZ High-Recoil Event}},
author = {Mattia Di Mauro and Halim Shaikh},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.06760},
eprint = {2609.06760},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06760},
note = {CC0},
}
RIS
TY - UNPB
TI - Solar Capture Tests of Inelastic Dark Matter after the LZ High-Recoil Event
AU - Mattia Di Mauro
AU - Halim Shaikh
PY - 2026
DA - 2026/09/06
PB - arXiv
DO - 10.48550/arxiv.2609.06760
UR - https://arxiv.org/abs/2609.06760
AB - The LUX-ZEPLIN (LZ) Collaboration has reported a $248$ keV nuclear-recoil candidate for which endothermic dark matter (DM) gives some of the largest local significances. We study Solar-capture constraints on three interpretations: a thermal Higgsino, a thermal pseudo-Dirac fermion with off-diagonal vector interactions, and neutron-philic endothermic spin-dependent scattering through 𝒪_4. The canonical full-density thermal Higgsino is excluded: its LZ-preferred splitting near 0.38 MeV lies well below the splitting required to suppress Solar capture sufficiently to satisfy the IceCube upper limits on DM annihilation in the Sun, δ≳0.51-0.56 MeV. For the pseudo-Dirac benchmark parameters that fit the LZ event, we find C_⊙=1.53×10^20 s^−1, while two-state kinetics limits the fixed-orbit annihilation rate to Γ_A≲4.4×10^14 s^−1, about 1.7×10^5 below the IceCube upper limit for the bb̅ channel. A semi-analytic treatment indicates that re-excitation cycles further cool the captured population, although a full phase-space calculation is required for its final distribution. For neutron-philic 𝒪_4 scattering at m_χ=1 TeV and δ=300 keV, finite-temperature capture gives C_⊙=3.98×10^17 s^−1, with nuclear-structure uncertainties giving an envelope (1.77-9.72)×10^17 s^−1. Under the equilibrium assumption, the upper edge remains about a factor $154$ below the IceCube upper limit for the bb̅ channel. We use bb̅ only as a soft-hadronic proxy because an exact constraint requires the model-specific annihilation spectrum. Solar capture therefore excludes the thermal-Higgsino interpretation but not endothermic explanations generically.
SN - 2331-8422
ER -