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

Abstract

We investigate SU(5) and SO(10) GUTs with vanishing scalar masses and trilinear scalar couplings at a scale higher than the unification scale. The parameter space of the models, further constrained by b-τYukawa coupling unification, consists of a common gaugino mass and of \tanβ. 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.

14 pages, 5 figures, JHEP style. Version accepted for publication in JHEP