Search for Halo Axions with Ferromagnetic Toroids (SHAFT Experiment)
ORAL
Abstract
We present the results of the SHAFT experiment to search for axion-like dark matter in the mass range from 12 peV to 12 neV. The experiment is sensitive to the oscillating magnetic field that would be sourced by an axion-like dark matter halo of our Galaxy interacting with a strong static magnetic field in the lab. We employ toroidal ferromagnetic cores made of powdered iron-nickel alloy to enhance the static magnetic field by a factor of 24. Using superconducting quantum interference devices (SQUIDs), we achieve a magnetic sensitivity of $150~\mathrm{aT}/\sqrt{\mathrm{Hz}}$. This sensitivity allows us to improve, over a part of our mass range, the existing laboratory limits on the electromagnetic coupling of axion-like dark matter, reaching $4 \times 10^{-11}~\mathrm{GeV}^{-1}$ at 20 peV with 95\% confidence level.
*We acknowledge support from the NSF grant no. 1806557, the Heising-Simons Foundation grant no. 2015-039, the Simons Foundation grant no. 641332, and the Alfred P. Sloan Foundation grant no. FG-2016-6728.
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