High Energy Neutrino Astronomy with IceCube

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Air shower detectors have observed cosmic rays with energies up to 3*10^20 eV. However, despite decades of work, their sources remain unknown. Cosmic-rays are charged, so they are bent in the interstellar magnetic fields and their tracks do not point back to their source. The accelerators for these cosmic rays are also expected to produce neutrino as 'by-products'. Because they penetrate strongly and travel in straight lines, neutrinos are the only particles that will 'point back' to these sources. In contrast, high energy (above 100 TeV) photons are absorbed through their interactions with starlight and cosmic microwave background photons and do not survive over astronomical distances. IceCube is a 1 km^3 neutrino observatory being built at the South Pole to study neutrino production in high-energy astrophysical sites, and to search for the sources of ultra-high energy cosmic rays. Flux calculations using different approaches find that a detector volume of this size is adequate to observe neutrino sources. Possible sources include active galactic nuclei, gamma-ray bursters, and supernova remnants. IceCube will also study other particle-physics topics: searches for Weakly Interacting Massive Particle (a possible Dark Matter candidate) annihilation in the Earth or the Sun, for signatures of supersymmetry in neutrino interactions, studies of neutrino properties, and for exotica such as magnetic monopoles or extra dimensions. This proposal requests funding support for postdocs and students in the LBNL IceCube group to work on the analysis of IceCube data. This work will benefit from LBNL's long experience with IceCube, which has given them an intimate knowledge of the hardware and software, particularly for simulation, reconstruction, calibration and data verification. The observation of extra-terrestrial neutrinos would have broader significance, by finding the accelerators in the universe and thereby answering one of the 11 questions posed in the National Research Council study on the Physics of the Universe: "Where do ultra-high energy particles come from?" The proposal also includes an Education and Outreach component, which will communicate these results to students and the general public.