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

We show that the desirable weak mixing angle sin2θW=0.2312 at mZ scale can be generated naturally in the SU(3)C×SU(3) model on M4×S1/(Z2×Z2′) 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.