Speaker: George Fuller (UCSD)

Nonlinear neutrino flavor transformation, the lepton number of the universe, and sterile neutrino dark matter

Experiments now force us into a corner where discovery of neutrino mixing at a mass-squared difference scale different from that of solar or atmospheric neutrinos may be tantamount to the discovery of a light "sterile" neutrino. In turn, through the simple nuclear physics of Big Bang Nucleosynthesis and observationally-inferred primordial light element abundances, this discovery could also imply the existence of a sizeable lepton number in the universe. The existence of light sterile neutrinos and a significant net lepton number heighten interest in sterile neutrino Dark Matter. This Dark Matter candidate is readily constrainable/detectable with existing and future x-ray observatories.