University of Minnesota Ph.D. dissertation. June 2017. Major: Physics. Advisor: Keith Olive. 1 computer file (PDF); viii, 107 pages.This thesis studies systematically non-supersymmetric models that contain dark matter candidates. The stability of the dark matter is guaranteed by a remnant Z 2 symmetry embedded naturally in SO(10). We build models base on various dark matter production mechanism, including the non-equilibrium thermal dark matter scenario, the weakly interactive massive particle scenario, and the asymmetric dark matter scenario. Although we start from very general assumptions on the choice of dark matter representation and the symmetry breaking pattern, the number of viable models is severely restricted by the requirement of gauge coupling unification. These models are then checked against several phenomenological constraints, such as the light neutrino masses, direct detection bounds on dark matter candidates and the proton decay lifetime. Finally, we demonstrate that the vacuum stability problem of the Standard Model can be evaded by one of our scalar dark matter models
