Maximal grand unification, gauge hierarchies, and baryon nonconservation

We study the constraints on the hierarchy of gauge-boson mass scales from low-energy physics in the maximal grand unification model based on the group SU(16). We show that for certain values of ${{sin}^2\theta }_W\left(m_W\right)$ and ${\alpha }_{\mathrm{strong}}\left(m_W\right)$ allowed by low-energy data, the intermediate mass scales associated with local $B-L$ symmetry and right-handed gauge interactions may be as low as ${10}^3$ GeV. We use a previously suggested method to study the Higgs-boson effects on these mass scales. We also discuss the implications for baryon nonconservation in this model and point out that the most likely $\Delta B\ne 0$ processes in simple versions of the model are the ones obeying $\Delta \mathrm{}(B-L)=0\mathrm{}$ selection rule.