UC Irvine

Neutralino dark matter is well motivated, but also suffers from two shortcomings: it requires gravity-mediated supersymmetry breaking, which generically violates flavor constraints, and its thermal relic density Omega is typically too large. We propose a simple solution to both problems: neutralinos freeze-out with Omega approximately 10-100, but then decay to approximately 1 GeV gravitinos, which are simultaneously light enough to satisfy flavor constraints and heavy enough to be all of dark matter. This scenario is naturally realized in high-scale gauge-mediation models, ameliorates small scale structure problems, and implies that "cosmologically excluded" models may, in fact, be cosmologically preferred.