Implications for minimal supersymmetry from grand unification and the neutralino relic abundance

We examine various predictions of the minimal supersymmetric standard model coupled to minimal supergravity. The model is characterised by a small set of parameters at the unification scale. The supersymmetric particle spectrum at low energy and the spontaneous breaking of the standard model itself are then generated radiatively. The previously considered predictions of the model now include the neutralino relic density which in turn provides bounds on the scale parameters. We find a remarkable consistency among several different constraints which imply all supersymmetric particle masses preferably within the reach of future supercolliders (Large Hadron Collider (LHC) and Superconducting Super Collider (SSC)). The requirement that the neutralino be the dominant component of (dark) matter in the flat Universe provides a lower bound on the spectrum of supersymmetric particles beyond the reach of the European Large Electron -Positron storage rings (LEP), and most likely also the Tevatron and LEP 200. (author)