First Search for Ultraheavy Dark Matter Using a Magnetically Levitated Particle

Abstract

We present the first search for ultraheavy dark matter using a magnetically levitated particle. The POLONAISE experiment uses a milligram-scale ferromagnet levitated in a superconducting trap, admitting a force sensitivity of $0.07\mathrm{fN}\mathrm{H}{\mathrm{z}}^{-1/2}$ and resolving impulses as small as $1\mathrm{TeV}/c$. Treating every candidate impulse as a possible dark matter event, we set optimum-interval upper limits on the neutron coupling ${\alpha }_n$ for dark matter interacting through a new light mediator. For dark matter masses $10^6\mathrm{GeV}/c^2\text{-}10^{15}\mathrm{GeV}/c^2$ and mediators lighter than $30\mathrm{meV}/c^2$, we exclude couplings as low as ${\alpha }_n=3.2\times 10^{-9}$ at $95\%$ confidence level and set leading constraints on the dark matter-neutron cross section for composite dark matter. Our results extend levitated sensing beyond the mass reach of optical levitation by seven orders of magnitude into the ultraheavy dark matter frontier.

6 pages, 6 appendices, 6 figures