Constraints on the minimal supergravity model from nonstandard vacua

We evaluate regions of parameter space in the minimal supergravity model where open-quote open-quote unbounded from below close-quote close-quote (UFB) or charge or color-breaking minima (CCB) occur. Our analysis includes the most important terms from the one-loop effective potential. We note a peculiar discontinuity of results depending on how renormalization group improvement is performed: One case leads to a UFB potential throughout the model parameter space, while the other typically agrees quite well with similar calculations performed using only the tree level potential. We compare our results with constraints from cosmology and naturalness and find a preferred region of parameter space which implies mg approx-lt 725 GeV, mq approx-lt 650 GeV, mW1 approx-lt 225 GeV, and mlR approx-lt 220 GeV. We discuss the consequences of our results for supersymmetry searches at various colliding beam facilities. copyright 1996 The American Physical Society