Interactions of ultra-high energy cosmic neutrinos in IceCube

Spencer Klein
Lawrence Berkeley National Laboratory & University of California, Berkeley

The IceCube neutrino observatory has observed astrophysical neutrinos with energies up to 10 PeV (1 PeV = 10^15 eV)), 20,000 times higher in energy than are studied with particle accelerators. In addition to providing information about astrophysical particle accelerators, they allow us to extend studies of neutrino interactions by many orders of magnitude upward in energy. I will discuss our diffuse neutrino results and present two neutrino-properties measurements: a measurement of the neutrino interaction cross-section, determined by measuring neutrino absorption in the Earth, and a measurement of the inelasticity, the fraction of neutrino energy transferred to the outgoing lepton. I will also present a new technique: coherent radio Cherenkov emission from ultra-high energy neutrino showers, and plans to build a radio-array to instrument ~100 km^3 of Antarctic ice. A new detector extend neutrino studies up to 10^20 eV – beyond the energy reach of CERN’s Large Hadron Collider.