KIPAC Seminar: Murmurs of Giants: Cosmic Rays and Neutrinos at the Energy Frontier

Abstract: Despite first observing cosmic rays with energies above an EeV (10^18 eV) in the 1960s, the source of these particles remains an open question. Modern observatories, in particular the Pierre Auger Observatory and Telescope Array, have firmly established that the cosmic ray spectrum continues up to ~10^20.3 eV and have significantly advanced our understanding of these particles. However, limited statistics, uncertainties in particle physics, and significant deflections in the Galactic magnetic field have made progress towards discovering their astrophysical source extremely challenging.

Multimessenger observations, in particular observations of neutrinos, have the potential provide key insights into the environments which produce these cosmic rays, and possibly even help identify their sources directly. Recent observations by the IceCube and KM3NeT Neutrino Observatories may constitute the first signs of neutrinos from the highest energy cosmic ray sources. In this talk, I will review the state of high-energy astroparticle data, explore implications of the highest energy neutrino observations, and discuss prospects for the future.