Search for Low-Mass Axion Dark Matter with ABRACADABRA-10 cm

Two of the most pressing questions in physics are the microscopic nature of the dark matter that comprises 84% of the mass in the Universe and the absence of a neutron electric dipole moment. These questions would be resolved by the existence of a hypothetical particle known as the quantum chromodynamics (QCD) axion. In this work, we probe the hypothesis that axions constitute dark matter, using the ABRACADABRA-10 cm experiment in a broadband configuration, with world-leading sensitivity. We find no significant evidence for axions, and we present 95% upper limits on the axionphoton coupling down to the world-leading level g(a gamma gamma) < 3.2 x 10(-11) GeV-1, representing one of the most sensitive searches for axions in the 0.41-8.27 neV mass range. Our work paves a direct path for future experiments capable of confirming or excluding the hypothesis that dark matter is a QCD axion in the mass range motivated by string theory and grand unified theories.

Automated summary

This study investigated the hypothesis that axions constitute dark matter and set 95% upper limits on the axion-photon coupling down to the world-leading level. The work opens a direct path for future experiments to confirm or exclude the hypothesis that dark matter is a QCD axion in the mass range motivated by string theory and grand unified theories.