Reconciling Neutralino relic Density with Yukawa Unified Supersymmetric Models

Supersymmetric grand unified models based on the gauge group SO(10) areespecially attractive in light of recent data on neutrino masses. The simplestSO(10) SUSY GUT models predict unification of third generation Yukawa couplingsin addition to the usual gauge coupling unification. Recent surveys of Yukawaunified SUSY GUT models predict an inverted scalar mass hierarchy in thespectrum of sparticle masses if the superpotential mu term is positive. Ingeneral, such models tend to predict an overabundance of dark matter in theuniverse. We survey several solutions to the dark matter problem in Yukawaunified supersymmetric models. One solution-- lowering the GUT scale mass valueof first and second generation scalars-- leads to u_R and c_R squark masses inthe 90-120 GeV regime, which should be accessible to Fermilab Tevatronexperiments. We also examine relaxing gaugino mass universality which may solvethe relic density problem by having neutralino annihilations via the Z or hresonances, or by having a wino-like LSP.Comment: 21 page file plus 9 figures; updated version to coincide with published versio