Number of fermion generations from a novel grand unified model

Abstract

Electroweak interactions based on the gauge group SU(3)L × U(1)X, coupled to the QCD gauge group SU(3)c, can predict the number of generations to be multiples of three. We first try to unify these models within SU(N) groups, using antisymmetric tensor representations only. After examining why these attempts fail, we continue to search for an SU(N) GUT that can explain the number of fermion generations. We show that such a model can be found for N = 9, with fermions in antisymmetric rank-1 and rank-3 representations only, and we examine the constraints on various masses in the model coming from the requirement of unification © 2014 The Author(s).