Brane webs and $O5$-planes
Gabi Zafrir
TL;DR
This work demonstrates that brane webs in orientifold $O5$ backgrounds robustly realize 5d fixed-point theories, including alternating $SO$ and $USp$ quivers and $D$-shaped $SU$ quivers, and enables engineering of $SO(N)$ theories with spinor matter through a nonperturbative mechanism. By analyzing Higgs branches, S-duality, and dualities, the authors uncover symmetry enhancements and map between different low-energy gauge descriptions, with explicit checks using the 5d superconformal index. The results provide a concrete framework for studying fixed points, dualities, and instanton-driven phenomena in these theories, and hint at possible six-dimensional uplifts. Overall, the paper extends the toolkit for constructing and validating 5d SCFTs via brane webs in orientifold backgrounds and highlights nonperturbative spinor matter as a key ingredient.
Abstract
We explore the properties of five-dimensional supersymmetric gauge theories living on $5$-brane webs in orientifold $5$-plane backgrounds. This allows constructing quiver gauge theories with alternating $USp(2N)$ and $SO(N)$ gauge groups with fundamental matter, and thus leads to the existence of new $5d$ fixed point theories. The web description can be further used to study non-perturbative phenomena such as enhancement of symmetry and duality. We further suggest that one can use these systems to engineer $5d$ $SO$ group with spinor matter. We present evidence for this claim.
