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T: Fachverband Teilchenphysik

T 22: Theoretische Astroteilchenphysik und Kosmologie 1

T 22.1: Talk

Monday, March 9, 2009, 17:00–17:15, M114

A successful cosmological model with selfinteracting Dark Matter — •Rainer Stiele¹ and Jürgen Schaffner-Bielich² — ¹Institut für Theoretische Physik, Goethe-Universität Frankfurt am Main — ²Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg

We investigated a model with interactions between Dark Matter particles whose crucial consequences are additive contributions to energy density and pressure. Their differing scaling behaviour from the common ones of radiation and matter results in an epoch prior to the radiation-dominated era where energy density and pressure of the universe were dominated by the contributions of the selfinteraction. Friedman equations together with the equation of state of the selfinteraction and its proportionality to the Dark Matter particle density necessitate that the selfinteracting Dark Matter decoupled while still relativistic. Hence to reach standard Warm Dark Matter particle masses additional degrees of freedom in thermal equilibrium at decoupling to those of the standardmodell particles are required. Tracking the evolution of the selfinteracting Dark Matter energy density depending on the Dark Matter parameters together with the restrictions on the total energy density at primordial nucleosynthesis allow to restrain the selfinteraction strength. The surprising result is that even interactions between Dark Matter particles of the strength of the strong interaction cannot be excluded. Furthermore the consequences on Dark Matter decoupling and structure formation in a selfinteracting dominated universe were explored.