New Limit on Axion-Like Dark Matter using Cold Neutrons

TL;DR

This study used cold neutrons in a Ramsey-type setup to search for axion-like dark matter particles, setting new constraints on their coupling to gluons across a specific mass range.

Contribution

It provides the first experimental constraints on ALP-gluon coupling using cold neutrons, improving limits in the ultra-light mass range.

Findings

No significant oscillating neutron EDM signal detected.

Set new upper limits on ALP-gluon coupling in the mass range $10^{-19}$ to $4 imes 10^{-12}$ eV.

Achieved the best limit of $C_G/f_a m_a = 2.7 imes 10^{13}$ GeV$^{-2}$.

Abstract

We report on a search for dark matter axion-like particles (ALPs) using a Ramsey-type apparatus for cold neutrons. A hypothetical ALP-gluon-coupling would manifest in a neutron electric dipole moment signal oscillating in time. Twenty-four hours of data have been analyzed in a frequency range from 23 $\mu$Hz to 1 kHz, and no significant oscillating signal has been found. The usage of present dark-matter models allows to constrain the coupling of ALPs to gluons in the mass range from $10^{-19}$ to $4 \times 10^{-12}$ eV. The best limit of $C_G$/$f_a m_a = 2.7 \times 10^{13}$ GeV$^{-2}$ (95\% C.L.) is reached in the mass range from $2 \times 10^{-17}$ to $2 \times 10^{-14}$ eV.