Color embeddings, charge assignments, and proton stability in unified gauge theories

• DOI: 10.1103/revmodphys.50.721
• Publication Date: 2002-07-27T04:44:41Z
• Authors: M. Gell-Mann; P. Ramond; R. Slansky
• Keywords: Gauge group; Color charge; Proton decay; Electric charge

Three problems in hypothetical unified theories of electromagnetic, weak, and strong interactions are discussed here. First, the problem embedding color any simple gauge group is solved, a complete classification where fermion restricted to ${1}^{c}$, ${3}^{c}$, ${\overline{3}}^{c}$ $\mathrm{S}{\mathrm{U}}_{3}^{c}$ given. Generalizations also indicated. Second, an unbroken ${\mathrm{U}}_{1}$ generated by electric charge embedded into each above assignments analyzed. Third, general stabilizing proton suitable atomic mass number $A$ studied for same set theories. It always possible define if not too small. In many these there must be fermions with weird values $A$: leptons $A\ensuremath{\ne}0$ quarks $\mathrm{A}\ensuremath{\ne}\frac{1}{3}$. Examples discussed. Some future directions research