Multipole analysis of IceCube data to search for dark matter accumulated in the Galactic halo IceCube Collaboration

Dark matter which is bound in the Galactic halo might self-annihilate and produce a flux of stable final state particles, e.g. high energy neutrinos. These neutrinos can be detected with IceCube, a cubic-kilometer sized Cherenkov detector. Given IceCube’s large field of view, a charactera e-mail: [email protected] b Earthquake Research Institute, University of Tokyo, Bunkyo, Tokyo 113-0032, Japan c NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA istic anisotropy of the additional neutrino flux is expected. In this paper we describe a multipole method to search for such a large-scale anisotropy in IceCube data. This method uses the expansion coefficients of a multipole expansion of neutrino arrival directions and incorporates signal-specific weights for each expansion coefficient. We apply the technique to a high-purity muon neutrino sample from the Northern Hemisphere. The final result is compatible with the nullhypothesis. As no signal was observed, we present limits on