Unification of gauge, Higgs and matter in extra dimensions

We consider the unification of gauge, Higgs as well as the matter fields in a 6D N=2 supersymmetric SU(8) gauge theory. The gauge symmetry SU(8) is broken down to SU(4)×SU(2)L×SU(2)R×U(1)2 in 4D through T2/Z6 orbifold compactification, and the theory is reduced to 4D N=1 supersymmetric Pati–Salam model. The electroweak Higgs fields as well as the third family of fermions are unified in the 6D N=2 gauge multiplet. The 6D bulk gauge interaction provides both gauge and Yukawa interactions for the third family predicting α1=α2=α3=αt=αb=ατ at the unification scale, in good agreement with experiment. Incorporation of the first and second family as well as other orbifolds are also briefly discussed.