ADMX SLIC: Results from a Superconducting LC Circuit Investigating Cold Axions

TL;DR

This paper reports the first use of a superconducting LC circuit in a haloscope experiment to search for low-mass axion dark matter, setting new exclusion limits in a previously unexplored frequency range.

Contribution

It introduces a tunable superconducting LC circuit for axion detection in the sub 2×10^{-7} eV mass range, expanding the experimental search methods for cold dark matter.

Findings

Excluded axion-photon coupling below 10^{-12} GeV^{-1} in the targeted mass range.

Demonstrated the feasibility of using piezoelectric tuning in superconducting LC circuits for axion searches.

Probed new parameter space in axion mass-coupling space at multiple magnetic field strengths.

Abstract

Axions are a promising cold dark matter candidate. Haloscopes, which use the conversion of axions to photons in the presence of a magnetic field to detect axions, are the basis of microwave cavity searches such as the Axion Dark Matter eXperiment (ADMX). To search for lighter, low frequency axions in the sub $2\times10^{-7}$ eV (50 MHz) range, a tunable lumped-element LC circuit has been proposed. For the first time, through ADMX SLIC (Superconducting Lc circuit Investigating Cold axions), a resonant LC circuit was used to probe this region of axion mass-coupling space. The detector used a superconducting LC circuit with piezoelectric driven capacitive tuning. The axion mass and corresponding frequency range $1.7498 -1.7519 \times10^{-7}$ eV (42.31 -- 42.36 MHz), $1.7734 - 1.7738 \times10^{-7}$ eV (42.88 -- 42.89 MHz), and $1.8007 - 1.8015 \times10^{-7}$ eV (43.54 -- 43.56 MHz) was covered at magnetic fields of 4.5 T, 5.0 T, and 7.0 T respectively. Exclusion results from the search data, for coupling below $10^{-12} \text{GeV}^{-1}$ are presented.