Constraints on fifth forces through perihelion precession of planets

Abstract

The equivalence principle is important in fundamental physics. The fifth force, as a describing formalism of the equivalence principle, may indicate the property of an unknown theory. Dark matter is one of the most mysterious objects in the current natural science. It is interesting to constrain the fifth force of dark matter. We propose a new method to use perihelion precession of planets to constrain the long-range fifth force of dark matter. Due to the high accuracy of perihelion precession observation, and the large difference of matter composition between the Sun and planets, we get one of the strongest constraints on the fifth force of dark matter. In the near future, the BepiColombo mission will be capable to improve the test by another factor of ten.