5D and 6D SCFTs from $\mathbb{C}^3$ orbifolds
Jiahua Tian, Yi-Nan Wang
TL;DR
The paper develops a unified framework for building 5d SCFTs from orbifold singularities $X=\mathbb{C}^3/\Gamma$ with $\Gamma\subset SU(3)$ by combining the 3d McKay correspondence with explicit geometric resolutions. It shows how to extract the 5d rank and flavor symmetry from group data via Ito–Reid, and how to determine the 1-form symmetry from the McKay quiver, while the resolution data yields the Coulomb-branch structure and potential IR gauge descriptions. It further connects the 5d theories to 6d $(1,0)$ SCFTs through elliptic fibrations and presents concrete examples including a new 6d theory from $\mathbb{C}^3/\Delta(48)$ and various $\Delta(3n^2)$, $\Delta(6n^2)$, and exceptional subgroups. Together, these results illuminate how geometry, group theory, and higher-dimensional SCFTs interrelate, and provide a roadmap for constructing and classifying new theories with precise flavor and 1-form symmetries.
Abstract
We study the orbifold singularities $X=\mathbb{C}^3/Γ$ where $Γ$ is a finite subgroup of $SU(3)$. M-theory on this orbifold singularity gives rise to a 5d SCFT, which is investigated with two methods. The first approach is via 3d McKay correspondence which relates the group theoretic data of $Γ$ to the physical properties of the 5d SCFT. In particular, the 1-form symmetry of the 5d SCFT is read off from the McKay quiver of $Γ$ in an elegant way. The second method is to explicitly resolve the singularity $X$ and study the Coulomb branch information of the 5d SCFT, which is applied to toric, non-toric hypersurface and complete intersection cases. Many new theories are constructed, either with or without an IR quiver gauge theory description. We find that many resolved Calabi-Yau threefolds, $\widetilde{X}$, contain compact exceptional divisors that are singular by themselves. Moreover, for certain cases of $Γ$, the orbifold singularity $\mathbb{C}^3/Γ$ can be embedded in an elliptic model and gives rise to a 6d (1,0) SCFT in the F-theory construction. Such 6d theory is naturally related to the 5d SCFT defined on the same singularity. We find examples of rank-1 6d SCFTs without a gauge group, which are potentially different from the rank-1 E-string theory.
