Test of non-Newtonian gravitational force at micrometer range
  We report an experimental test of non-Newtonian gravitational forces at mi- crometer range. To experimentally subtract off the Casimir force and the electrostatic force background, differential force measurements were performed by sensing the lateral force between a gold sphere and a density modulated source mass using a soft cantilever. The current sensitivity is limited by the patch electrostatic force, which is further improved by two dimensional (2D) force mapping. The preliminary result sets a model independent constraint on the Yukawa type force at this range. 
Pengshun Luo, Jianbo Wang, Shengguo Guan, Wenjie Wu, Zhaoyang Tian,   Shanqing Yang, Chenggang Shao, Jun Luo
gr-qc hep-ph