UNC-CH Physics and Astronomy Colloquium

Kevork Abazajian, University of California, Irvine

“Cosmological Neutrinos”

Cosmology has entered a precision era, allowing to make inferences of the constituency of the Universe to the sub-percent level on quantities like the density of matter. The density of light, relativistic components like neutrinos can also be inferred, so that limits on the mass of the neutrinos are an order of magnitude stronger from cosmology than the laboratory, albeit with some important caveats. The neutrino sector could hold some surprises, including dark/sterile species that may constitute the dark matter. An unexplained line in X-ray astronomy may indicate a signal of this sort of dark matter, which has initiated several follow-up astronomical and laboratory searches.