SMOOTH HYBRID INFLATION

We propose a variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models. The observed temperatur e perturbations of cosmic background radiation can be reproduced with natural values of the parameters of the theory and a grand unification scale which is consistent with the unification of the minimal supersy mmetric standard model gauge couplings as measured at CERN LEP. The te rmination of inflation is smooth and does not produce any topological defects. Finally, we present a specific supersymmetric model where our smooth hybrid inflationary scenario is realized.