SUSY-GUTs, SUSY-Seesaw and the neutralino dark matter

Abstract

We will consider a SUSY-SU(5) with one right-handed neutrino with a large top like Yukawa coupling. Assuming universal soft masses at high scale we compute the low-energy spectrum and subsequently the neutralino LSP relic density taking also into consideration SU(5) as well as the see-saw running effects above the gauge coupling unification scale. We found that there exists no viable region in parameter space for tan β less than or similar to 35. The τ[overline] coannihilation process starts becoming efficient for tan β greater than or similar to 35-40. However, this process is significantly constrained by the limited range in which the stau is lighter than the neutralino. Infact, for a given tan β we find that there exists an upper bound on the lightest neutralino mass (M-chi-1(0)) in this region. The A-pole funnel region appears at very large tan β similar or equal to 45-50, while the focus-point region does not make an appearance till large (m(0),M-1/2), namely a few TeV. Large A(0) terms at high scale can lead to extended regions consistent with WMAP constraints and remove the upper bounds in the stau coannihilation regions.