Abstrakt
We scrutinize the physical viability of the minimal nonsupersymmetric SO(10) grand unified theory with the scalar sector 45 circle plus 126 circle plus 10C, in which the unified symmetry is broken by the former two representations, and a realistic Yukawa sector is supported by the last two. Alongside the known issue of a relatively low grand unified theory scale (and thus overly fast proton decay) encountered in minimally fine-tuned scenarios, we identify a very general problem of the model: the inability to properly accommodate a Standard-Model-like low-energy Higgs doublet in the perturbative regime.