Multipole analysis of IceCube data to search for dark matter accumulated
  in the Galactic halo
  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 characteristic 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
null-hypothesis. As no signal was observed, we present limits on the
self-annihilation cross-section averaged over the relative velocity
distribution $<\sigma v>$ down to $1.9\cdot
10^{-23}\,\mathrm{cm}^3\mathrm{s}^{-1}$ for a dark matter particle mass of
$700\,\mathrm{GeV}$ to $1000\,\mathrm{GeV}$ and direct annihilation into
$\nu\bar{\nu}$. The resulting exclusion limits come close to exclusion limits
from $\gamma$-ray experiments, that focus on the outer Galactic halo, for high
dark matter masses of a few TeV and hard annihilation channels.
