Gravitational Gauge Fields and the Cosmological Constant

ADSTRACT We describe field theories for which the action is completely independent of the metric and connection of the space-time manifold. The metric in our approach is no more a fundamental field than a hadron field is a fundamental field in &CD. The fundamental fields in the action are O(5) gauge fields and combinations of these fields are interpreted as the metric and connection so that conventional general relativity is obtained. Remarkably, all renormalizable matter actions for scalar, spinor and Yang-Mills gauge fields can be made metric independent. Significantly we find a new elementary symmetry of the action which implies the cosmological constant must vanish. Finally, we discuss the quantum theory resulting from these ideas.