Test of the Gravitational Inverse-Square Law at Laboratory Distances

Abstract

The inverse-square distance dependence of the gravitational force has been tested over a range of approximately 2 to 5 cm, by use of a test mass suspended from a torsion balance to probe the gravitational field inside a mass tube. The result supports an inverse-square law. Assuming a force deviating from inverse square by a factor [$1+\ensuremath{\epsilon} \mathrm{ln}\ensuremath{\gamma}$ (cm)] it is found that $\ensuremath{\epsilon}=(1\ifmmode\pm\else\textpm\fi{}7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.