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.

Comments: 6 pages, 6 appendices, 6 figures