New experimental limits on non-Newtonian forces in the micrometer-range

TL;DR

This study measures short-range forces between gold plates to set new experimental limits on hypothetical non-Newtonian forces at micrometer scales, constraining theories with extra dimensions and gauge bosons.

Contribution

The paper provides the most stringent bounds to date on Yukawa-type forces in the 0.4 to 4 micrometer range, using precise torsion pendulum measurements.

Findings

Established new bounds for forces between 0.4 and 4 micrometers.

Set a lower limit of 70 TeV on the Planck scale in extra-dimensional theories.

Confirmed the Casimir force as the dominant short-range interaction in the measured range.

Abstract

We report measurements of the short-range forces between two macroscopic gold-coated plates using a torsion pendulum. The force is measured for separations between 0.7 $\mu$m and 7 $\mu$m, and is well described by a combination of the Casimir force, including the finite-temperature correction, and an electrostatic force due to patch potentials on the plate surfaces. We use our data to place constraints on the Yukawa-type "new" forces predicted by theories with extra dimensions. We establish a new best bound for force ranges 0.4 $\mu$m to 4 $\mu$m, and, for forces mediated by gauge bosons propagating in $(4+n)$ dimensions and coupling to the baryon number, extract a $(4+n)$-dimensional Planck scale lower limit of $M_*>70$ TeV.