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

Le résumé fourni par la source

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 $$\langle \sigma _{\mathrm {A}} v\rangle $$ down to $$1.9\times 10^{-23}\,\text {cm}^3\,\text {s}^{-1}$$ for a dark matter particle mass of 700–1,000 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.

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