Torsion-balance tests of the weak equivalence principle

TL;DR

This paper reviews recent high-precision torsion-balance experiments testing the weak equivalence principle, discussing implications for antimatter, dark matter, and future experimental improvements.

Contribution

It summarizes recent torsion-balance tests achieving unprecedented precision in comparing accelerations of different materials.

Findings

Differential accelerations measured at the part in 10^{13} level.

Results have implications for antimatter and dark matter gravitational properties.

Discussion of potential future experimental enhancements.

Abstract

We briefly summarize motivations for testing the weak equivalence principle and then review recent torsion-balance results that compare the differential accelerations of beryllium-aluminum and beryllium-titanium test body pairs with precisions at the part in $10^{13}$ level. We discuss some implications of these results for the gravitational properties of antimatter and dark matter, and speculate about the prospects for further improvements in experimental sensitivity.