A new experimental baseline for testing the weak equivalence principle at the Bremen drop tower

Free-fall experiments to test the weak equivalence principle are in progres s at the drop tower in Bremen. The differential acceleration of two test ma sses made from different materials is being measured by means of a supercon ducting-quantum-interference-device- (SQUID-) based sensing technique. Thes e pseudo-Galilean tests are aimed at determining the Eotvos ratio to an acc uracy of better than 10(-12). The free-fall height of the experimental caps ules is 110 m, translating into an experimental time of about 4.5 s. The SQ UID-based sensing system guarantees a high measuring resolution of 10(-12) mHz(-1/2) for the relative positions of the test masses.