Neutralino relic density in supersymmetric GUTs with no-scale boundary conditions above the unification scale

摘要

We investigate SU(5) and SO(10) GUTs with vanishing scalar masses and trilinear scalar couplings above the unification scale. The parameter space of the models, further constrained by b-tau Yukawa coupling unification, consists of a common gaugino mass and of tanbeta. We analyze the low energy phenomenology, finding that A-pole annihilations of neutralinos and/or coannihilations with the lightest stau drive the relic density within the cosmologically preferred range in a significant region of the allowed parameter space. Implications for neutralino direct detection and for CERN LHC experiments are also discussed.