Spin-independent scattering of pseudoscalar-mediated dark matter
Abstract
Dark matter with pseudoscalar couplings provides a well-motivated scenario in which direct-detection signals are suppressed at tree level, since the scattering off nuclei is both spin-dependent and momentum suppressed. While spin-independent scattering is absent at tree level, it arises at one loop and can provide the leading direct-detection signal. We revisit this scenario in a general sub-electroweak effective field theory with a light pseudoscalar mediator, including interactions through to mass-dimension-six. We compute the matching onto the quark and gluon operators relevant for direct detection to determine whether this scenario could be detectable at future experiments, while also requiring consistency with the observed dark matter relic-abundance and indirect-detection limits. We find that while models with a pseudoscalar mediator can generate spin-independent cross sections above the neutrino floor, this generally requires additional new physics below the TeV scale.
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BibTeX
@misc{bell2026spinindependent,
title = {{Spin-independent scattering of pseudoscalar-mediated dark matter}},
author = {Nicole F. Bell and Giorgio Busoni and Peter Cox and Laura W. Fang and John Gargalionis and Jayden L. Newstead and Ewan N. V. Wallace and Martin J. White and Anthony G. Williams},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12336},
eprint = {2609.12336},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12336},
}
RIS
TY - UNPB
TI - Spin-independent scattering of pseudoscalar-mediated dark matter
AU - Nicole F. Bell
AU - Giorgio Busoni
AU - Peter Cox
AU - Laura W. Fang
AU - John Gargalionis
AU - Jayden L. Newstead
AU - Ewan N. V. Wallace
AU - Martin J. White
AU - Anthony G. Williams
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12336
UR - https://arxiv.org/abs/2609.12336
AB - Dark matter with pseudoscalar couplings provides a well-motivated scenario in which direct-detection signals are suppressed at tree level, since the scattering off nuclei is both spin-dependent and momentum suppressed. While spin-independent scattering is absent at tree level, it arises at one loop and can provide the leading direct-detection signal. We revisit this scenario in a general sub-electroweak effective field theory with a light pseudoscalar mediator, including interactions through to mass-dimension-six. We compute the matching onto the quark and gluon operators relevant for direct detection to determine whether this scenario could be detectable at future experiments, while also requiring consistency with the observed dark matter relic-abundance and indirect-detection limits. We find that while models with a pseudoscalar mediator can generate spin-independent cross sections above the neutrino floor, this generally requires additional new physics below the TeV scale.
ER -