COSMOLOGICAL RELIC DENSITY FROM MINIMAL SUPERGRAVITY WITH IMPLICATIONS FOR COLLIDER PHYSICS

Working within the framework of the minimal supergravity model with ga uge coupling unification and radiative electroweak symmetry breaking, we evaluate the cosmological relic density from lightest neutralinos p roduced in the early universe. Our numerical calculation is distinct i n that it involves direct evaluation of neutralino annihilation cross sections using helicity amplitude techniques; and thus avoids the usua l expansion as a power series in terms of neutralino velocity. Thus, o ur calculation includes relativistic Boltzmann averaging, neutralino a nnihilation threshold effects, and proper treatment of integration ove r Breit-Wigner poles. We map out regions of parameter space that give rise to interesting cosmological dark matter relic densities. We compa re these regions with recent calculations of the reach for supersymmet ry by CERN LEP 2 and Fermilab Tevatron Main Injector era experiments. The cosmologically favored regions overlap considerably with the regio ns where large trilepton signals are expected to occur at the Tevatron . The CERN LHC pp collider can make a thorough exploration of the cosm ologically favored region via gluino and squark searches. In addition, over most of the favored region, sleptons ought to be light enough to be detectable at both LHC and at a root s = 500 GeV e(+)e(-) collider .