New N=2 superconformal field theories from S-folds

TL;DR

This work classifies and constructs four-dimensional $\mathcal{N}=2$ SCFTs arising from D3-branes probing $N=2$ S-folds, introducing an infinite family $\mathcal{T}_{G,\ell}^{(r)}$ generated by partial Higgsings of the original $\mathcal{S}_{G,\ell}^{(r)}$ theories. It develops a universal ECB structure, derives Coulomb-branch spectra, moduli spaces, and vacuum branches using a synthesis of 6d $\mathcal{N}=(1,0)$ torus reductions, class-S technology, and the SCFT/VOA correspondence, and confirms these results against geometric F-theory data via flavor central charges and anomaly relations. A central achievement is the explicit, rank-by-rank construction of the $\mathcal{T}_{G,\ell}^{(r)}$ family and a transparent ECB-based Higgsing path $\mathcal{S}^{(r)} \rightarrow \mathcal{T}^{(r)} \rightarrow \mathcal{S}^{(r-1)}$, which organizes the spectrum and central charges. The paper also provides several 6d-to-4d realizations and demonstrates, in many cases, that these models admit Class S descriptions, furnishing concrete trinions and Schur indices that corroborate the proposed identifications. Overall, the results deliver a cohesive framework for understanding a broad class of interacting $\mathcal{N}=2$ SCFTs from S-folds and their 6d origins, with explicit checks via holography, anomaly matching, and VOA methods.

Abstract

We study the four-dimensional N=2 superconformal field theories that describe D3-branes probing the recently constructed N=2 S-folds in F-theory. We introduce a novel, infinite class of superconformal field theories related to S-fold theories via partial Higgsing. We determine several properties of both the S-fold models and this new class of theories, including their central charges, Coulomb branch spectrum, and moduli spaces of vacua, by bringing to bear an array of field-theoretical techniques, to wit, torus-compactifications of six-dimensional N=(1,0) theories, class S technology, and the SCFT/VOA correspondence.