Torsion-balance probes of fundamental physics

TL;DR

Torsion-balance experiments are highly sensitive tools used to test fundamental physics, including gravity's universality, short-distance gravity behavior, and Lorentz invariance, with implications for unifying fundamental forces.

Contribution

This white paper reviews the use of torsion-balance experiments to explore ultra-feeble forces and fundamental physics beyond current theories.

Findings

Confirmed the universality of free fall within experimental limits

Set new constraints on extra dimensions and new bosons at meV scales

Provided tests of Lorentz invariance at Planck-scale energies

Abstract

This white paper is submitted as part of Snowmass2013 (subgroup CF2). The extraordinary sensitivity of torsion-balances can be used to search for the ultra-feeble forces suggested by attempts to unify gravity with the other fundamental interactions. The motivation, the results and their implications as well as the future prospects of this work are summarized. The experiments include tests of the universality of free fall (weak equivalence principle), probes of the short-distance behavior of gravity (inverse-square law tests for extra dimensions and exchange forces from new meV scale bosons), and Planck-scale tests of Lorentz invariance (preferred-frame effects, non-commutative geometries).