Thursday, April 24, 2008, 16:00
WHGA Auditorium
L. Baudis, Zürich University
Abstract:
We have strong evidence on all cosmic scales, from galaxies to the
largest structures ever observed, that there is more matter in the
universe than we can see. Galaxies and clusters would fly apart unless
they would be held together by material which we call dark, because it
does not emit electromagnetic radiation. Although the amount of dark
matter and its distribution are fairly well established, we are clueless
regarding its composition. Leading candidates are Weakly Interacting
Massive Particles (WIMPs), which are 'cold' thermal relics of the Big
Bang, ie moving non- relativistically at the time of structure
formation. An example is the neutralino, or the lightest supersymmetric
particle, which arises naturally in supersymmetric extensions of the
Standard Model of particle physics and has a typical mass of about 100
GeV. Another example is the lightest Kaluza-Klein excitation in
theories with universal extra dimensions. I will review current
searches for these hypothetical particles via elastic scattering from
nuclei in deep underground detectors. The focus will be on recent
results, and on the most promising techniques for the near future.