An Improved Torsion Balance Test of the Equivalence Principle Towards the Sun

Abstract

We search for violations of the Equivalence Principle towards the Sun using a rotating torsion balance apparatus. We set 95\%-confidence limits on violations with beryllium and aluminum test bodies of ${\eta }_{\odot ,Be-Al}\le 2.1\times 10^{-13}$. These results are a factor of four improvement of previously reported results towards the Sun and a $\sim 20\%$ improvement on previous torsion balance tests regardless of source.