Yukawa Unification and Neutralino Dark Matter in SU(4)_c \times SU(2)_L \times SU(2)_R

Understand

We consider a left-right symmetric SU(4)_c \times SU(2)_L \times SU(2)_R (4-2-2) model with gravity mediated supersymmetry breaking.

• We find that with 4-2-2 compatible non-universal gaugino masses, t-b-\tau Yukawa coupling unification is consistent with neutralino dark matter abundance and with constraints from collider experiments (except (g-2)_{\mu}).
• The gluino mass lies close to that of the lightest neutralino, so that the gluino co-annihilation channel plays an important role in determining the neutralino relic abundance.
• By relaxing the Yukawa unification constraint we find stau and stop masses as low as 200-220 GeV.