Sheng Fong: Seesaw Cosmology

Thursday 1 Oct 2026, 11:00 → 12:00 Europe/Ljubljana

A/1-106 - Seminarska soba fizike (F5) (Jamova)

In this talk, we will look at seesaw cosmology where we assume the energy density of the Universe is dominated by nonrelativistic scalar field after inflation, and perturbative reheating occurs when the scalar field transfers its energy to the Standard Model sector through right-handed neutrinos (RHNs) responsible for light-neutrino masses via the type-I seesaw mechanism. When produced relativistically and sufficiently long lived, the RHNs generate a characteristic sequence of inflaton, relativistic-RHN, nonrelativistic-RHN, and Standard Model radiation domination. Then, we investigate the implications of seesaw cosmology for dark-matter production. We further study the regime where the phase space of RHN is saturated and quantum statistics becomes relevant, obtaining a new power law in the temperature evolution during the scalar field domination era.