München 2009 – scientific programme
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T: Fachverband Teilchenphysik
T 22: Theoretische Astroteilchenphysik und Kosmologie 1
T 22.2: Talk
Monday, March 9, 2009, 17:15–17:30, M114
Hidden gauginos of an unbroken U(1): Cosmological constraints and phenomenological prospects — Alejandro Ibarra1, Andreas Ringwald2, and •Christoph Weniger2 — 1Physik Department T30, Technische Universität München, Garching — 2Deutsches Elektronen-Synchrotron DESY, Hamburg
An unbroken hidden U(1) gauge group which interacts with the standard model only via a small kinetic mixing with hypercharge decouples from the observable sector and is completely unconstrained by current experiments. We point out that this decoupling is elevated in the supersymmetric counterpart of this scenario, due to effects of supersymmetry breaking, and derive constraints from cosmological and astrophysical arguments. We firstly concentrate on the case where the gaugino of the hidden U(1) gauge group is the LSP and makes up all of the observed dark matter. We show constraints on the model parameters from avoiding overclosure of the Universe and from requiring successful Big Bang Nucleosynthesis and structure formation. Secondly, in scenarios with a light gravitino as the LSP and the hidden U(1) gaugino as the NLSP, we show that the bounds on the reheating temperature that come from potentially long lived charged MSSM relics are considerably relaxed. Finally, we consider the case of an anomalously small mixing parameter, where χ≪10−16, and discuss signatures from cosmic rays.