Studies on the unfolding of the atmospheric neutrino spectrum with IceCube 59 using the TRUEE algorithm

Abstract

The measurement of the atmospheric neutrino energy spectrum provides information about the diffuse neutrino flux from extragalactic sources. A relative increase of the spectrum toward higher energies could be evidence for neutrino producing hadronic processes in the cosmic high energy accelerators, such as active galactic nuclei or gamma ray bursts. IceCube is currently the largest neutrino detector on Earth and is placed in the antarctic ice at the geographic South Pole. IceCube permits the detection of neutrinos with energies beyond 10^6 GeV. Since the acceptance and the resolution of neutrino telescopes suffer from the finite resolution and limited acceptance, a regularized unfolding method is used to extract the energy distribution of neutrinos from the measured observables. For AMANDA, the unfolding was done with the RUN algorithm. Based on the basic concept of this program and for data analyses in the ROOT frame, a new deconvolution algorithm (TRUEE) has been written and tested. With this new algorithm, studies on the analysis of the atmospheric neutrino spectrum measured with the IceCube 59 string configuration are presented.