High Energy Physics Seminars

ics High Energy
Thursday, September 17, 2009
4:00 PM
Physics Building, Room 313
Note special date.
Note special time.
Note special room.
Ralf Ehrlich [Host: Craig Dukes]
University of Maryland
"The Search for Neutralino Dark Matter with the AMANDA Neutrino Telescope"
There is convincing indirect evidence based on cosmological data that approximately one quarter of the universe is made of dark matter. However, to this date there is no direct detection of the dark matter and its nature is unknown. Many theories suggest that dark matter is made of supersymmetric particles, and the most promising candidate out of the supersymmetric particles is the lightest neutralino. These neutralinos can get gravitationally trapped in the Earth, where they eventually annihilate. The annihilation products decay and a fraction of the decay products are muon-neutrinos, which can be detected with the AMANDA/IceCube neutrino telescope in the ice at the South Pole. Neutrinos cannot be detected directly. However, there is a small possibility that they interact with the nuclei of the ice via a charged current interaction and "create" charged leptons. These charged leptons continue to travel in almost the same direction as the neutrinos. As long as their speed is higher than the speed of light of the ice, they emit Cherenkov radiation which can be captured by photomultipliers installed inside the ice. A hypothetical muon-neutrino flux from neutralino annihilations inside Earth should show up as an excess over the expected muon-neutrino flux from atmospheric neutrinos produced in the northern hemisphere. No significant excess has been observed, yielding an upper limit on the neutrino flux that could have come from neutralino annihilation.

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