AST 95-29225 PI: Lev Kofman Inflation and the Origin of Matter in the Universe According to inflationary cosmology, all the elementary particles which we see now were not present at the moment of the Big Bang, but were created by the decaying scalar field at the end of the inflationary stage. The process of creation of matter during the decay of the scalar field and the subsequent process of thermalization of the created particles is called reheating. The theory of reheating is still incomplete, and is interrelated with the dark matter problem. Recent studies by the PI and his colleagues have discovered more efficient methods of reheating which have important implications for cosmological models. For example, standard inflation theory results in a flat universe (Omega = 1); with different reheating parameters, a different distribution of density fluctuations may result, with a different amount of dark matter. Since current observations produce densities well below those of a flat universe, the amount of dark matter can be critical in establishing whether inflation theory does indeed hold. The PI intends to investigate the production of elementary particles when the new reheating methods are allowed for, and to examine the influence of the cosmological constant on the models with the new reheating methods, using an analytic approach.
