Exclusion Limits on Hidden-Photon Dark Matter near 2 neV from a Fixed-Frequency Superconducting Lumped-Element Resonator

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We present the design and performance of a simple fixed-frequency superconducting lumped-element resonator developed for axion and hidden photon dark matter detection.

• A rectangular NbTi inductor was coupled to a Nb-coated sapphire capacitor and immersed in liquid helium within a superconducting shield.
• The resonator was transformer-coupled to a DC SQUID for readout.
• We measured a quality factor of $\sim$40,000 at the resonant frequency of 492.027 kHz and set a simple exclusion limit on $\sim$2 neV hidden photons with kinetic mixing angle $\varepsilon\gtrsim1.5\times10^{-9}$ based on 5.14 hours of integrated noise.