New Test of the Gravitational 1/r² Law at Separations down to 52 m

We tested the gravitational 1/r(2) law using a stationary torsion-balance detector and a rotating attractor containing test bodies with both 18-fold and 120-fold azimuthal symmetries that simultaneously tests the 1/r(2) law at two different length scales. We took data at detector-attractor separations between 52 mu m and 3.0 mm. Newtonian gravity gave an excellent fit to our data, limiting with 95% confidence any gravitational-strength Yukawa interactions to ranges < 38.6 mu m.