Leptogenesis in the superstring inspired E 6 model

Abstract

The observed baryon asymmetry of the Universe is elegantly explained in the framework of the baryogenesis via leptogenesis scenario. We analyze various aspects of this scenario including the influence of perturbations of the energy density and space–time metric perturbations on the generation of the lepton and baryon asymmetries. We also consider conversion of the lepton asymmetry into the baryon asymmetry and investigate the effects associated with the fact, that the lepton asymmetry induces nonzero chemical potentials of the other species. We estimate upper bound on the asymmetry in the Standard Model and in the superstring inspired E6 model. Properties of this model relevant for leptogenesis are discussed in detail. The baryogenesis via leptogenesis scenario predicts nonzero masses of the neutrinos, measured in the oscillation experiments. We calculate cross sections of the charged and neutral current coherent pion production by neutrino scattering off nuclei relevant for the interpretation of the experimental results.