Weak mixing angle and the SU(3) C× SU(3) model on M4× S1/( Z2× Z2′)

Abstract

We show that the desirable weak mixing angle sin 2 θ W =0.2312 at m Z scale can be generated naturally in the SU(3) C × SU(3) model on M 4× S 1/( Z 2× Z 2′) where the gauge symmetry SU(3) is broken down to SU(2) L × U(1) Y by orbifold projection. For a supersymmetric model with a TeV scale extra dimension, the SU(3) unification scale is about hundreds of TeVs at which the gauge couplings for SU(3) C and SU(3) can also be equal in the mean time. For the non-supersymmetric model, SU(2) L × U(1) Y are unified at order of 10 TeV. These models may serve as good candidates for physics beyond the SM or MSSM.