Detection of ultra-high energy cosmic neutrinos with the IceCube neutrino observatory and its implications to the origin of ultra-high energy cosmic rays
We review the present status of the search for ultra-high energy (UHE) cosmic neutrinos with the IceCube Neutrino Observatory. The IceCube neutrino observatory has currently realized the best sensitivity on detection of cosmic neutrinos in UHE energy range of PeV up to 10EeV (=10^10 GeV), by the standard neutrino detection technique measuring ultra-violet Cherenkov light emissions. The most updated results from the data obtained by the full instrumentation volume of the IceCube optical sensor array are reported. Two neutrino-induced events have been found to pass the final signal search criteria. Their primary neutrino energies are estimated to be beyond 1 PeV, indicating that they are the most energetic neutrinos we have ever seen in the history of neutrino astrophysics. We present their features in some details, followed by discussions on the implication to origin of ultra-high energy cosmic rays.
