Sensitivity of the IceCube neutrino detector to dark matter annihilating in dwarf galaxies

Abstract

In this paper, we compare the relative sensitivities of gamma-ray and neutrino observations to the dark matter annihilation cross section in leptophilic models such as have been designed to explain PAMELA data. We investigate whether the high energy neutrino telescope IceCube will be competitive with current and upcoming searches by gamma-ray telescopes, such as the Atmospheric Çerenkov Telescopes (H.E.S.S., VERITAS, and MAGIC), or the Fermi Gamma-Ray Space Telescope, in detecting or constraining dark matter particles annihilating in dwarf spheroidal galaxies. We find that after 10 years of observation of the most promising nearby dwarfs, IceCube will have sensitivity comparable to the current sensitivity of gamma-ray telescopes only for very heavy (m_X ≳ 7  TeV) or relatively light (m_X ≲ 200  GeV) dark matter particles which annihilate primarily to μ^+μ^-. If dark matter particles annihilate primarily to τ^+τ^-, IceCube will have superior sensitivity only for dark matter particle masses below the 200 GeV threshold of current Atmospheric Çerenkov Telescopes. If dark matter annihilations proceed directly to neutrino-antineutrino pairs a substantial fraction of the time, IceCube will be competitive with gamma-ray telescopes for a much wider range of dark matter masses.