No abstract

By using a torsion pendulum and a rotating eightfold symmetric attractor with dual modulation of both the interested signal and the gravitational calibration signal, a new test of the gravitational inverse-square law at separations down to 295  μm is presented. A dual-compensation design by adding masses on both the pendulum and the attractor was adopted to realize a null experiment. The experimental result shows that, at a 95% confidence level, the gravitational inverse-square law holds (|α|≤1) down to a length scale λ=59  μm. This work establishes the strongest bound on the magnitude α of Yukawa-type deviations from Newtonian gravity in the range of 70-300  μm, and improves the previous bounds by up to a factor of 2 at the length scale λ≈160  μm.

Short-range tests of the gravitational inverse-square law are very important for finding new interactions. In order to further improve the constraints on the Yukawa-like gravitational force, we propose a new scheme based on the torsion balance, where the speculative Yukawa-like gravitational force between the pendulum and the attractor is substantially increased by increasing the area of the test mass and the source mass. A dual-compensation design is used to realize a null experiment, which can release the accuracy requirement on some geometric parameters. The calculation result shows that, at the 95% confidence level, the new design can establish the strongest bound on the magnitude α of the Yukawa violation at the range of 40– 800 µm with the total error of about 2.0×10−17 Nm, and improve the previous bounds about one order of magnitude at the length scale λ ≈ 300µm.