A search for anisotropy of inertial mass using a free precession technique

The idea that the inertial mass of a body may a.rise from a gravitational coupling with distant matter has led to suggestions that the concentration of matter near the centre of our galaxy may result in an anisotropy of inertia at the earth which could be detected experimentally. In particular, Cocconi and Salpeter (1958, l960) have pointed out that such an anisotropy might cause shifts in energy levels of atoms and nuclei in magnetic fields. They suggest, for example, that in a nucleus which can be regarded as a single p_(3/2) nucleon moving in an isotropic central potential the energies of the states with magnetic quantum numbers m_1 = ± 3/2 would he increased slightly if the magnetic field were parallel to the direction of the centre of the Galaxy, and the energies of the states with m_1 = ± l/2 would be decreased by an equal amount; while if the magnetic field were perpendicular to the direction of the centre of the Galaxy the energies would be shifted in the opposite directions.