Neutralino with the Right Cold Dark Matter Abundance in (Almost) Any Supersymmetric Model

Abstract

We consider non-standard cosmological models in which the late decay of a scalar field $ϕ$ reheats the Universe to a low reheating temperature, between 5 MeV and the standard freeze-out temperature of neutralinos of mass $m_χ$. We point out that in these models all neutralinos with standard density $Ω_{\rm std} \gtrsim 10^{-5} (100 {\rm GeV}/m_χ)$ can have the density of cold dark matter, provided the right combination of the following two parameters can be achieved in the high energy theory: the reheating temperature, and the ratio of the number of neutralinos produced per $ϕ$ decay over the $ϕ$ field mass. We present the ranges of these parameters where a combination of thermal and non-thermal neutralino production leads to the desired density, as functions of $Ω_{\rm std}$ and $m_χ$.