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

We tested the gravitational 1 /r² 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 /r² law at two different length scales. We took data at detector-attractor separations between 52 μ 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 μ m .