We investigate how simple grand unified theories with a precocious-unification mass can be constructed. The maximal local symmetry of 2mn left-handed fermions and their left-handed antiparticles is shown to be a viable candidate, where m and n are the number of families and colors, respectively. The predictions of such a model are studied.

• Received 21 April 1984

DOI:https://doi.org/10.1103/PhysRevD.31.181