Search for low mass WIMPs with the AMANDA neutrino telescope

Abstract: Recent measurements show that dark matter makes up at least one fifth of the total energy density of the Universe. The nature of the dark matter is one of the biggest mysteries in current particle physics and cosmology.Big Bang nucleosynthesis limits the amount of baryonic matter that can exist, and shows that the dark matter has to be non-baryonic. Particle physics provides some candidates for non-baryonic matter that could solve the dark-matter problem, weakly interacting massiveparticles (WIMPs) being the most popular. If these particles were created in the early Universe a substatial relic abundance would exist today. WIMPs in our galactic halo could be gravitationally bound in the Solar System and accumulate inside heavy bodies like the Earth. Supersymmetric extensions to the Standard Model give a viable WIMP dark matter candidate in the form of the lightest neutralino. This thesis describes an indirect search for WIMPs by the neutrino signature from neutralino annihilation at the core of the Earth using the AMANDA detector. As opposed to previous dark matter searches with AMANDA, this work focuses on the hypothesis of a relatively light WIMP particle with mass of 50-250GeV/c2The AMANDA neutrino telescope is an array of photomultiplier tubes installed in the clear glacier ice at the South Pole which is used as Cherenkov medium. Data taken with AMANDA during the period 2001-2003 is analyzed. The energy threshold of the detector is lowered by the use of a local correlation trigger, and the analysis is taylored to select vertically upgoing low energy events. No excess above the expected atmospheric neutrino background is found. New limits on the flux of muons from WIMP annihilations in the center of the Earth are calculated.