The idea of unification attempts to explain the complicated structure of the Standard Model (SM) in terms of fewer fundamental forces and/or matter fields. However, traditional GUTs based on SU(5) and Spin(10) say nothing about the existence of three generations of fermions, nor the pattern of their Yukawa couplings to the Higgs. We propose an alternative path whereby the SM flavour symmetries are unified with electroweak symmetry via an SU(4) x Sp(6) x Sp(6) anomaly-free gauge theory. All the SM fermions are unified into just two fundamental fields, a left- and a right-handed Weyl fermion each with 24 components. We show how, via a sequence of symmetry breaking transitions that land on the SM, the hierarchical SM flavour structure is naturally generated.

University of Zurich