We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Delta a=(0.6+/-3.1)x10^-15 m/s^2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The Eoetvoes parameter is eta=(0.3+/-1.8)x10^-13. By analyzing our data for accelerations towards the center of the Milky Way we find equal attractions of Be and Ti towards galactic dark matter, yielding eta=(-4 +/- 7)x10^-5. Space-fixed differential accelerations in any direction are limited to less than 8.8x10^-15 m/s^2 with 95% confidence.
@article{arxiv.0712.0607,
title = {Test of the Equivalence Principle Using a Rotating Torsion Balance},
author = {S. Schlamminger and K. -Y. Choi and T. A. Wagner and J. H. Gundlach and E. G. Adelberger},
journal= {arXiv preprint arXiv:0712.0607},
year = {2008}
}
Comments
4 pages, 4 figures; accepted for publication in PRL