Search for ultralight dark matter in the SuperMAG high-fidelity dataset

Abstract

Ultralight dark matter, such as kinetically mixed dark-photon dark matter (DPDM) or axionlike-particle dark matter (axion DM), can source an oscillating magnetic-field signal at Earth's surface. Previous work searched for this signal in a publicly available dataset of global magnetometer measurements maintained by the SuperMAG collaboration. This ``low-fidelity" dataset reported measurements with a 1-minute time resolution, allowing the search to set leading direct constraints on DPDM and axion DM with Compton frequencies $f_{\mathrm{DM}}\le 1/(1\min )$ [corresponding to masses $m_{\mathrm{DM}}\le 7\times 10^{-17}\mathrm{eV}$]. More recently, a dedicated experiment undertaken by the SNIPE Hunt collaboration has also searched for this same signal at higher frequencies $f_{\mathrm{DM}}\ge 0.5\mathrm{Hz}$ (or $m_{\mathrm{DM}}\ge 2\times 10^{-15}\mathrm{eV}$). In this work, we search for this signal of ultralight DM in the SuperMAG ``high-fidelity" dataset, which features a 1-second time resolution, allowing us to probe the gap in parameter space between the low-fidelity dataset and the SNIPE Hunt experiment. The high-fidelity dataset exhibits lower geomagnetic noise than the low-fidelity dataset and features more data than the SNIPE Hunt experiment, making it a powerful probe of ultralight DM. Our search finds no robust DPDM or axion DM candidates. We set constraints on DPDM and axion DM parameter space for $10^{-3}\mathrm{Hz}\le f_{\mathrm{DM}}\le 0.98\mathrm{Hz}$ (or $4\times 10^{-18}\mathrm{eV}\le m_{\mathrm{DM}}\le 4\times 10^{-15}\mathrm{eV}$). Our results are the leading direct constraints on both DPDM and axion DM in this mass range, and our DPDM constraint surpasses the leading astrophysical constraint in a narrow range around $m_{A^{\prime }}\approx 2\times 10^{-15}\mathrm{eV}$.

Comments: 18 pages, 5 figures. Published version