Supersymmetric Standard Model from the heterotic string (II) Original Research Article

We describe in detail a image orbifold compactification of the heterotic image string which leads to the (supersymmetric) Standard Model gauge group and matter content. The quarks and leptons appear as three 16-plets of image, two of which are localized at fixed points with local image symmetry. The model has supersymmetric vacua without exotics at low energies and is consistent with gauge coupling unification. Supersymmetry can be broken via gaugino condensation in the hidden sector. The model has large vacuum degeneracy. Certain vacua with approximate image symmetry have attractive phenomenological features. The top quark Yukawa coupling arises from gauge interactions and is of the order of the gauge couplings. The other Yukawa couplings are suppressed by powers of Standard Model singlet fields, similarly to the Froggatt–Nielsen mechanism.