Supersymmetry and Inflation

A variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models and reproduces the observed temperature perturbations of cosmic background radiation with natural values of the parameters is presented. The theory is consistent with the unification of the minimal supersymmetric standard model gauge couplings as measured at LEP. The termination of inflation is smooth and does not produce any topological defects. Numerical investigation of the cosmological evolution of the system shows that for almost all initial values of the fields we do get an adequate amount of inflation. Finally, the "reheating" process following inflation and the production of the baryon asymmetry of the universe via a primordial lepton asymmetry are briefly discussed and some important implications for right handed neutrino Majorana masses are investigated.