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

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 mχ. We point out that in these models all neutralinos with standard density Ωstd > ∼ 10−5(100GeV/mχ) 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 Ωstd and mχ.