SUSY GUTS DARK MATTER

We examine the cosmology of the lightest neutralino (chi) in a minimal SUSY GUT model. Our analysis incorporates the ensuing relations among the squark, slepton, and gaugino masses, and takes into account the recent experimental constraints on the parameter space. We consider a general neutralino state and compute its cosmological relic density resulting from pair annihilation into all allowed final states. Our analysis reveals a rich structure of resonances due to s-channel exchanges, and shows that some previous, studies using pure neutralino states in "nearly" pure regions of parameter space give rather poor estimates for m(chi) < M(W). We show that in the regions of parameter space favored by cosmology, the neutralino is a "nearly" pure bino state with m(chi) greater than or similar to 100 GeV. The SUSY GUTs mass relations then imply m(l) greater than or similar to 200 GeV and m(q,g) greater than or similar to 600 GeV, all well within the reach of future hadron colliders.