Proton Stability, Dark Matter and Light Color Octet Scalars in Adjoint SU(5) Unification

The unification of gauge interactions in the context of Adjoint SU(5) and its phenomenological consequences are investigated. We show the allowed mass spectrum of the theory which is compatible with proton decay, and discuss the possibility to have a cold dark matter candidate. Due to the upper bounds on the proton decay partial lifetimes, tau (p --> K^+ nubar) < 9.3 10^{36} years and tau(p --> pi^+ nubar) < 3.0 10^{35} years, the theory could be tested at future proton decay experiments. The theory predicts also light scalar color octets which could be produced at the Large Hadron Collider.