Neutrino Astronomy and Cosmic Rays with IceCube

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Air shower detectors have observed cosmic rays with ultra high energies. However, their sources, nuclear composition and acceleration mechanism(s) remain unknown. Some possible sources include active galactic nuclei, gamma-ray bursters, and/or supernova remnants. In contrast to charged cosmic rays which bend in interstellar magnetic fields, the neutrinos that are expected to be produced in these accelerators travel in straight lines, so do point back to their sources. The IceCube observatory being built at the South Pole to search for these sources will soon reach 1 cubic km in volume. The accompanying 1 square km surface array (IceTop) detects air showers with energies above 300 TeV. Combining shower data with measurements of TeV muons from IceCube makes it possible to study the cosmic-ray composition. By using IceCube to veto events containing muons, it is also possible to identify photon-initiated showers. This award will provide funds to study three topics pertaining to the origins and composition of cosmic rays: a search for a diffuse neutrino flux from the entire sky, a measurement of the transverse momentum (pT) spectrum of high pT muons in air showers, and a search for PeV photons from the Milky Way and the Magellanic Clouds. During the three years of this grant, they will either observe extra-terrestrial neutrinos or set limits below the Waxman-Bahcall bound. The pT spectrum of these muons can be calculated using perturbative QCD, thus avoiding the phenomenological models that are required in other composition studies. The group will continue contributing to IceCube Maintenance and Operations work in the areas of optical module simulation and calibration, detector verification and calibration and in Monte Carlo simulation production. The Education and Outreach component will communicate this forefront research to students and the general public, through presentations at elementary through high schools and public lectures. They educate both undergraduate and graduate students, by involving them in their research.