Search for dark matter with an LC circuit

Abstract

The focus on the dark matter search has expanded to include low-mass particles such as axions or axionlike particles, and novel theoretical schemes extending the phenomenological landscape, within QCD and beyond, also garnered additional interest in recent decades. Assuming dark matter is composed of axions, in the presence of a solenoidal magnetic field, they induce a displacement current that gives rise to a toroidal magnetic field. The weakly interacting slender particle detection with an $LC$ circuit (WISPLC) is a precision direct detection experiment that will search for light dark matter candidates such as axionlike particles in parts of the parameter space previously unexplored. We present two detection schemes of the signal in a pickup loop capturing the flux of this toroidal magnetic field. WISPLC operates in a broadband and a resonant scheme where an $LC$ circuit is used to enhance the signal with an expected $Q$ factor $\ensuremath{\sim}{10}^{4}$. Taking into account the irreducible flux noise of the detector, we estimate the sensitivity of the experiment in the axion mass range between ${10}^{\ensuremath{-}11}$ and ${10}^{\ensuremath{-}6}\text{ }\text{ }\mathrm{eV}$ to reach a detectable axion-photon coupling of ${g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}\ensuremath{\approx}{10}^{\ensuremath{-}15}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$, making it possible to probe mass ranges corresponding to ultralight axions motivated by string theory. The WISPLC experiment is fully funded and currently in the construction phase.