Anomalies on orbifolds with gauge symmetry breaking

We consider the breaking of 5D SUSY G = SU(N +K) gauge symmetry into H = SU(N) × SU(K) × U(1) on an orbifold S/(Z2 × Z ′ 2). There appear two independent fixed points: one respects the full bulk gauge symmetry G while the other contains only the unbroken gauge symmetry H . In the model with one bulk (N + K)-plet, giving a K-plet as the zero mode, we show that localized non-abelian gauge anomalies appear at the fixed points: the H gauge anomalies are equally distributed on both fixed points and the H − (G/H) − (G/H) gauge anomalies contribute only at the fixed point with G symmetry. We also find that when we add a brane K̄-plet in the field theoretic limit of a bulk field, the theory with the unbroken gauge group can be consistent up to the introduction of a bulk non-abelian Chern-Simons term. Moreover, for our set of bulk and brane fields, we find that a nonzero log Fayet-Iliopoulos term is radiatively generated at the fixed point with H , which gives rise to the localization of the bulk zero mode at that fixed point and modifies the massive modes without changing the KK mass spectrum.