PhD defense by Morten Ankersen Medici – University of Copenhagen

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PhD defense by Morten Ankersen Medici

Title: Search for Dark Matter Annihilation in the Galactic Halo using IceCube

Abstract: The existence of dark matter has by now been demonstrated to such a de- gree that the next step is to understand what actually constitute this unknown gravitational mass. The total amount of matter in the universe cannot be explained without the introduction of a particle beyond the Standard Model, and with the right properties of this hypothesized particle, it is possible to look for a signal from dark matter annihilation. In this work, the dark matter particle candidate of weakly interacting massive particles shall be presented, and the possibilities of observing it’s self-annihilation to neutrinos shall be pursued with the IceCube Neutrino Observatory located in the dark clear ice deep underneath the South Pole.

An in ll to IceCube with a denser instrumentation allows the detection of neutrinos with energies down to 10 GeV. By using this sub-detector as the ducial volume, and the rest of IceCube as a veto detector for atmospheric muons it is possible to search for a neutrino signals form the center of the Milky Way located on the souther hemisphere. In this thesis, a complete analysis is carried out on data from 1004 days of IceCube data, looking for an excess of neutrinos consistent with the dark matter halo of the Milky Way over a uniform atmospheric background. No signi cant excess is ob- served, and constraints are presented for the thermally averaged product of the self-annihilation cross-section and the relative speed ⟨𝜎𝑣⟩, which for the annihilation of a 100 GeV WIMP through 𝑊+𝑊−, result in a limit at ⟨𝜎𝑣⟩ = 3.84 · 10−23cm3s−1. The result of the present analysis improves the previous IceCube limits below masses of weakly interacting massive particles of 500 GeV and constitute current world leading results of weakly interacting massive particles annihilting to neutrino for masses between 50 and 200 GeV.