Cosmology in natural GUT
Maekawa, Nobuhiro (Nagoya Univ.)

It has been studied that the anomalous U(1) gauge symmetry plays an important role not only in explainingthe various hierarchies of quark and lepton masses and mixings but also in solving serious problems of SUSY GUT, the doublet-triplet splitting problem, under the natural assumption that all the interactions which are allowed by the symmetry are included with O(1) coefficients. We would like to discuss the cosmology in the natural GUT scenario. We discuss some of the following topics, the vacuum selection by particle production, possibility of warm inflation, baryogenesis, and dark matter production.