Starobinsky Inflation: From Non-SUSY to SUGRA Realizations

We review the realization of Starobinsky-type inflation within induced-gravity supersymmetric (SUSY) and non-SUSY models. In both cases, inflation is in agreement with the current data and can be attained for sub-Planckian values of the inflation. The corresponding effective theories retain perturbative unitarity up to the Planck scale and the inflation mass is predicted to be 3 . 10(13) GeV. The supergravity embedding of these models is achieved by employing two gauge singlet chiral superfields, a superpotential that is uniquely determined by a continuous.. and a discrete Z(n). symmetry and several (semi) logarithmic Kahler potentials that respect these symmetries. Checking various functional forms for the noninflation accompanying field in the Kahler potentials, we identify four cases which stabilize it without invoking higher order terms.