Null Test of Newtonian Inverse-Square Law at Submillimeter Range with a Dual-Modulation Torsion Pendulum

Abstract

A null experimental test of the Newtonian inverse-square law at submillimeter range using a torsion pendulum was presented. Under the dual modulations of both the expected signal and the gravitational torque for calibration, our data concluded with 95% confidence that no new forces were observed and any gravitational-strength Yukawa forces ($|\alpha |\ge 1$) must have a length scale $\lambda <66\mu \mathrm{m}$, agreeing well with the latest result of the Eöt-wash group. Our result sets a unification energy scale of $M^{*}\ge 2.8\mathrm{TeV}/c^2$ for the two compactified extra space dimensions with the same size $R^{*}<47\mu \mathrm{m}$.