Special Physics Seminar

Astrophysical Neutrinos from the Lowest to the Highest Energies

Nathan Whitehorn

University of California, Berkeley

Neutrinos are the universe's second-most-common particle, after photons. The detection of astrophysical neutrinos at energies of an MeV, starting in the 1960s, has had profound impacts on our understanding of fundamental physics, bringing us neutrino oscillations, confirming our understanding of the engines of supernovae, and proving that the Sun is nuclear powered. In the last decade, we have for the first time detected neutrinos at the extremes of the energy spectrum and from cosmological distances, with the indirect detection of the sub-eV cosmic neutrino background produced in the Big Bang and the direct detection of a diffuse background of neutrinos at energies exceeding a PeV of unknown origin from beyond the galaxy. Moving from these initial detections to precision measurements of both of these populations promises to greatly enrich our understanding of astrophysics, particle physics, and cosmology. I will discuss the current state of these measurements and prospects for the future, focusing on the IceCube Neutrino Observatory and the recently deployed 3rd generation South Pole Telescope.