Special Discovery Seminar
Anne Schukraft (Aachen)
The search for an astrophysical diffuse neutrino flux with IceCube
The IceCube Neutrino Observatory located at the geographic South Pole is the largest neutrino detector in the world. With an instrumented volume of 1km3 of Antarctic ice, it provides sensitivity to neutrinos from GeV to EeV energies. This energy range covers a large part of the atmospheric neutrino spectrum, but also allows to search for high-energy neutrinos from beyond our Earth and Galaxy. Such neutrinos would be ideal messenger particles in astroparticle physics, because they propagate unaffected through the Universe and would carry information on the yet unknown sources and acceleration mechanism of cosmic rays. A promising approach to search for a signal of extragalactic neutrinos is the search for a high-energy diffuse neutrino flux, which is sensitive to the cumulative flux from all potential neutrino sources. Such a flux can be reasonably high for large source populations of, e.g., Active Galactic Nuclei, even if individual source fluxes are below the detection threshold. The experimental signature of isotropically distributed astrophysical sources is an excess of high-energy neutrinos over the background of lower-energetic atmospheric neutrinos. Although a background in the search for an extragalactic neutrino flux, atmospheric neutrinos are an interesting research topic themselves. Above TeV energies, a significant contribution of prompt atmospheric neutrinos from the decay of heavy mesons containing a charm quark is expected. Such a prompt neutrino flux has not been measured yet, but would allow an experimental test of charm production cross sections at high energies. In the low-energy range below 100 GeV, IceCube complements classical neutrino oscillation experiments with its sensitivity to the deficit of atmospheric muon neutrinos at 25 GeV.
Date: Thursday, 29/11/12
Place: Auditorium A, Blegdamsvej 17, 2100, Copenhagen Ø