Solar Spin-Dependent Dark Matter-Neutron Cross Section Constraints: The Lost Case
Abstract
The Sun has long served as a natural dark matter detector, capturing halo particles that scatter with solar nuclei and electrons and subsequently produce indirect signals from dark matter annihilation that can be probed by either neutrino or γ-ray instruments. Previous efforts have computed cross-section constraints for dark matter scattering with electrons, as well as spin-independent and spin-dependent dark matter-proton scattering. However, the spin-dependent dark matter-neutron scattering scenario has been neglected, despite its importance in direct detection. For the first time, we compute the capture and evaporation rates for spin-dependent dark matter-neutron scattering in the Sun, including odd-neutron isotope targets in the current standard solar model. Comparing the predicted annihilation signals against current neutrino and γ-ray observations, and projecting the reach of upcoming detectors, we find that solar constraints exceed direct detection limits for several annihilation channels. For models in which the dark matter annihilates into long-lived mediators, these constraints can extend below the neutrino fog.
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BibTeX
@misc{nguyen2026solar,
title = {{Solar Spin-Dependent Dark Matter-Neutron Cross Section Constraints: The Lost Case}},
author = {Thong T. Q. Nguyen and Carlos Blanco and Tim Linden},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.00118},
eprint = {2609.00118},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.00118},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Solar Spin-Dependent Dark Matter-Neutron Cross Section Constraints: The Lost Case
AU - Thong T. Q. Nguyen
AU - Carlos Blanco
AU - Tim Linden
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.00118
UR - https://arxiv.org/abs/2609.00118
AB - The Sun has long served as a natural dark matter detector, capturing halo particles that scatter with solar nuclei and electrons and subsequently produce indirect signals from dark matter annihilation that can be probed by either neutrino or γ-ray instruments. Previous efforts have computed cross-section constraints for dark matter scattering with electrons, as well as spin-independent and spin-dependent dark matter-proton scattering. However, the spin-dependent dark matter-neutron scattering scenario has been neglected, despite its importance in direct detection. For the first time, we compute the capture and evaporation rates for spin-dependent dark matter-neutron scattering in the Sun, including odd-neutron isotope targets in the current standard solar model. Comparing the predicted annihilation signals against current neutrino and γ-ray observations, and projecting the reach of upcoming detectors, we find that solar constraints exceed direct detection limits for several annihilation channels. For models in which the dark matter annihilates into long-lived mediators, these constraints can extend below the neutrino fog.
ER -