We consider a scalar-metric gauge theory of gravity with an independent, metric, connection, and dilaton. The role of the dilaton is to provide the scale of all masses, via its vacuum expectation value. In this theory, we study the renormalization-group flow of the dilaton potential, taking into account threshold effects at the Planck scale. Because of the running of the VEV of the dilaton all particles that would naively seem to have masses larger than Planck’s mass may actually not propagate. This could solve the problem of unitarity in these theories.

• Received 28 December 1994

DOI:https://doi.org/10.1103/PhysRevD.52.896