CONSTRAINTS FROM INFLATION ON SCALAR-TENSOR GRAVITY THEORIES

We show how observations of the perturbation spectra produced during i nflation may be used to constrain the parameters of general scalar-ten sor theories of gravity, which include both an inflaton and dilaton fi eld. An interesting feature of these models is the possibility that th e curvature perturbations on superhorizon scales may not be constant d ue to nonadiabatic perturbations of the two fields. Within a given mod el, the tilt and relative amplitude of the scalar and tensor perturbat ion spectra gives constraints on the parameters of the gravity theory, which may be comparable with those from primordial nucleosynthesis an d post-Newtonian experiments.