Laboratory Search for Spin-dependent Short-range Force from Axion-Like-Particles using Optically Polarized 3He gas

TL;DR

This study searches for short-range spin-dependent forces possibly caused by axion-like particles using polarized helium-3 gas, setting new upper bounds on their coupling constants over sub-millimeter distances.

Contribution

It introduces a novel experimental approach using polarized 3He gas to constrain axion-like particle interactions at short ranges, providing tighter bounds than previous experiments.

Findings

Established new upper bounds on scalar and pseudoscalar couplings.

Constrained axion-like particle interactions in the 2e-3 to 2e-5 eV mass range.

Demonstrated the effectiveness of NMR frequency shifts in detecting short-range forces.

Abstract

The possible existence of short-range forces between unpolarized and polarized spin-1/2 particles has attracted the attention of physicists for decades. These forces are predicted in various theories and provide a possible new source for parity (P) and time reversal (T) symmetry violation. We use an ensemble of polarized 3He gas in a cell with a 250 um thickness glass window to search for a force from scalar boson exchange over a sub-millimeter ranges. This interaction would produce a NMR frequency shift as an unpolarized mass is moved near and far from the polarized ensemble. We report a new upper bound on the product g_{s}g_{p}^{n} of the scalar couplings to the fermions in the unpolarized mass, and the pseudoscalar coupling of the polarized neutron in the 3He nucleus for force ranges from 1e-4 to 1e-2 m, which corresponds to a mass range of 2e-3 to 2e-5 eV for the scalar boson.