New Constraints on Dark Photon Dark Matter with Superconducting Nanowire Detectors in an Optical Haloscope

TL;DR

This paper presents a novel experimental approach using superconducting nanowire detectors in an optical haloscope to search for dark photon dark matter, setting new limits on its properties in the eV mass range.

Contribution

The work introduces LAMPOST, a proof-of-concept experiment utilizing multilayer dielectric haloscopes and SNSPDs to improve constraints on dark photon dark matter.

Findings

No evidence for dark photon dark matter in the 0.7-0.8 eV range.

Achieved a dark count rate of ~6×10⁻⁶ counts/sec with SNSPDs.

Improved existing limits on kinetic mixing parameter ε by up to a factor of two.

Abstract

Uncovering the nature of dark matter is one of the most important goals of particle physics. Light bosonic particles, such as the dark photon, are well-motivated candidates: they are generally long-lived, weakly-interacting, and naturally produced in the early universe. In this work, we report on LAMPOST (Light $A'$ Multilayer Periodic Optical SNSPD Target), a proof-of-concept experiment searching for dark photon dark matter in the eV mass range, via coherent absorption in a multi-layer dielectric haloscope. Using a superconducting nanowire single-photon detector (SNSPD), we achieve efficient photon detection with a dark count rate (DCR) of $\sim 6\times10^{-6}$ counts/s. We find no evidence for dark photon dark matter in the mass range of $\sim 0.7$-$0.8$ eV with kinetic mixing $\epsilon \gtrsim 10^{-12}$, improving existing limits in $\epsilon$ by up to a factor of two. With future improvements to SNSPDs, our architecture could probe significant new parameter space for dark photon and axion dark matter in the meV to 10 eV mass range.