Fooling the dark matter constraint in low reheating temperature cosmological models

by Graciela Gelmini (Unknown)

Thursday 18 Oct 2007, 14:00 → 15:00 Europe/Zurich

TH Theory Conference Room (CERN)

Requesting the relic abundace of dark matter candidates to be equal to or lower than the dark matter abundance, is an important constraint on particle models. However the relic abundance of these candidates, such as the neutralino, depends on the history of the Universe before Big Bang Nucleosynthesis, an epoque that cannot be reached observationally. The standard relic abundance calculations rely on a few but powerful assumptions on what happened in the Universe them, however other assumptions are equally possible. We will talk mostly of the implications of cosmological models in which the highest temperature of the last radiation dominated epoque in the Universe is low (say in the GeV's or lower) and argue that (almost) all supersymmetric models, as seen at the LHC scale, could provide neutralinos with the right abundance to be the dark matter. Thus, the dark matter particle, if found and studied experimentaly, will shead light on cosmology before BBN.