Experimental Constraint on an Exotic Spin- and Velocity-Dependent Interaction in the Sub-meV Range of Axion Mass with a Spin-Exchange Relaxation-Free Magnetometer

TL;DR

This study uses a highly sensitive magnetometer to search for exotic spin- and velocity-dependent interactions, setting new limits on axion-like particles in the sub-meV mass range.

Contribution

It introduces an experimental method employing a SERF magnetometer to constrain exotic interactions between polarized electrons and unpolarized nucleons.

Findings

Set an upper limit on coupling strength around 10^{-19}

Provided constraints on axion mass m_a  10^{-3} eV

Demonstrated sensitivity with 82 hours of data collection

Abstract

We conducted a search for an exotic spin- and velocity-dependent interaction for polarized electrons with an experimental approach based on a high-sensitivity spin-exchange relaxation-free (SERF) magnetometer, which serves as both a source of polarized electrons and a magnetic-field sensor. The experiment aims to sensitively detect magnetic-fieldlike effects from the exotic interaction between the polarized electrons in a SERF vapor cell and unpolarized nucleons of a closely located solid-state mass. We report experimental results on the interaction with 82 h of data averaging, which sets an experimental limit on the coupling strength around $10^{-19}$ for the axion mass $m_a \lesssim 10^{-3}$ eV, within the important axion window.