GRAVITATIONAL LIGHT DEFLECTION AND PROPAGATION DELAY IN NONSYMMETRIC THEORIES OF GRAVITY

The gravitational deflection of light by the Sun and the closely related gravitational propagation delay are polarization dependent in any theory of gravity which couples the antisymmetric part of a nonsymmetric-tensor gravitational field to the electromagnetic field. This polarization dependence is a global consequence of the breakdown of the Einstein equivalence principle. The present version of Moffat's nonsymmetric gravitation theory, the prototype for the theories we study, predicts that light grazing the limb of the Sun is deflected by about a fifth of a milliarcsecond more then it is linearly polarized with its magnetic field lying in the plane in which the light is deflected than when it is orthogonally polarized. The next generation of light-deflection experiments will stringently test this prediction.