Null Test of Newtonian Inverse-Square-Law at Short Range: Current Status and Developments

Motivated by a variety of novel theories that predict new effects, we will test Newtonian inverse-square law (ISL) at several sub-millimeter separations using a torsion pendulum in its horizontal direction. We had tested ISL at separations ranging down to 176µm, previous result stated that no new effects were observed. [L. C. Tu, S. G. Guan, J. Luo, C. G. Shao and L. X. Liu, Phys. Rev. Lett. 98 (2007), 201101.] On the basis of before, an improved ISL experiment (IISL) has been proposed, detecting distance will close up to 120µm and prospective result will set a constraint on Yukawa interactions with |α|≥1 at 95% confidence for λ≪ 33 µm, which will improve previous short-range constraints by one order at least.