Speaker
Description
Axion-like particles (ALPs) are well-motivated extensions to the Standard Model and could form a dark matter field that oscillates at a frequency proportional to their mass. Because the value of the ALP mass could be anywhere in the range of $10^{-22}$ to 10 eV/c$^2$, it is important to search across a broad frequency range. We present a new search for ALPs over nine orders of magnitude in mass using a pair of atomic comagnetometers operating as a dark matter field interferometer [1]. Our sensors use alkali metal and noble gas atoms in the same vapor cell, where spin interactions between the atoms suppress the response of the sensor to slow ($\lesssim 1$ Hz) magnetic fluctuations, while enabling sensitivity to spin-dependent interactions [2]. Data from the two comagnetometers, located in Kraków, Poland, and Mainz, Germany, allow us to search for a correlated ALP-induced pseudomagnetic interaction with atomic spins. We model the coherence properties of the ALP field and construct a signal model that remains valid across nine orders of magnitude in frequency, allowing us to take advantage of the expected spatio-temporal correlations in the data. No significant ALP candidate was found, and we set new limits on ALP couplings to neutrons, protons, and electrons, improving previous constraints by up to three orders of magnitude.
[1] D. Gavilan-Martin, G. Lukasiewicz, M. Padniuk, E. Klinger, M. Smolis, et al., Searching for dark matter with a 1000 km baseline interferometer (2024), arXiv:2408.02668.
[2] T. W. Kornack and M. V. Romalis, Dynamics of two overlapping spin ensembles interacting by spin exchange, Phys. Rev. Lett. 89, 253002 (2002).
