11 februari 2009
Nikhef colloquium at 15:30h in room H331
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By Herbert Dreiner, Physikalisches Institut Bonn
How light can the Lightest Supersymmetric Particle be?
Abstract: The lightest supersymmetric particle (LSP) is typically consiered to be the lightest neutralino, which is an admixture of the supersymmetric partner of the photon, the Z-boson, as well as the two electrically neutral Higgs bosons required in supersymmetry. The properties of the LSP are essential for future supersymmetry searches at the LHC since we expect them to arise in all supersymmetric events. We investigate the present lower mass bound on such a neutralino in a general supersymmetric Standar Model. We consider constraints from $e^+e^-$ Colliders, from precision observables, from rare meson decays, from supernova cooling and from dark matter. We find that a massless neutralino is consistent with all present experiments and observations.