Gauss’s law test of gravity at short range

A null test of the gravitational inverse-square law can be performed by testing Gauss’s law for the field. We have constructed a three-axis superconducting gravity gradiometer and carried out such a test. A lead pendulum weighing 1500 kg was used to produce a time-varying field. This experiment places a new (2σ) limit of α=(0.9±4.6)×${10}^{\mathrm{-}4}$ at λ=1.5 m, where α and λ are parameters of the generalized potential φ=-(GM/r)(1+α${\mathit{e}}^{\mathrm{-}\mathit{r}/\lambda }$).