Speaker
Description
Asymptotic grand unification (aGUT) replaces conventional fixed-scale unification by ultraviolet-safe flows toward a common interacting fixed point. Five-dimensional orbifold gauge theories are a natural arena for aGUT model building, but viability requires both a stable orbifold vacuum and consistent UV fixed points. I present general stability criteria for gauge breaking on $S^1/(\mathbb{Z}_2\times\mathbb{Z}_2^\prime)$ and a systematic classification of symmetry-breakingpatterns in bulk $SU(N)$, $SO(N)$, and $Sp(N)$ theories. Applying these criteria singles out viable routes, including a unique $SU(6)$ pathway to the Standard Model and an $SU(8)$ realization with an intermediate Pati-Salam stage. I then discuss the exceptional-group case: under minimal assumptions, stable orbifold vacua do not yield a minimal exceptional (non-SUSY) aGUT, motivating non-minimal ingredients. Finally, I summarize one-loop renormalization results for 5D gauge-Yukawa theories, deriving conditions for simultaneous UV fixed points in gauge, Yukawa, and scalar couplings. These conditions provide a useful discriminator between genuinely UV-consistent 5D models and effective descriptions.
