A new rank-2 Argyres-Douglas theory
Justin Kaidi, Mario Martone
TL;DR
The paper proposes a new rank-2 Argyres-Douglas theory ${\rm AD}({{\mathfrak{c}}_2})$ as an IR fixed point on the Coulomb branch of a mass-deformed $G_2$ gauge theory with four fundamentals, built without invoking the Seiberg-Witten curve. It bootstraps the Higgs and Coulomb branch data using geometric constraints, computes a consistent central-charge and flavor data set, and identifies a corresponding VOA that requires an extension of $\widehat{\mathfrak{sp}(4)}_{-{13}/{6}}$ by four dimension-$\tfrac{3}{2}$ generators. The Schur index and its Higgsing limit corroborate the Higgs/Coulomb data, while the vacuum character satisfies a degree-4 modular differential equation with $(c_{2d},h_1,h_2)=(-26,-\tfrac{4}{3},-\tfrac{7}{6})$, supporting the proposed VOA. A Class ${\mathcal S}$ construction from the $A_4$ (2,0) theory on a two-punctured sphere with an irregular puncture and a $\mathbb{Z}_2$ twist matches the central charges, Higgs branch, and flavor data, reinforcing the non-Lagrangian interpretation and expanding the landscape of Argyres-Douglas theories.
Abstract
We provide evidence for the existence of a new strongly-coupled four dimensional $\mathcal{N}=2$ superconformal field theory arising as a non-trivial IR fixed point on the Coulomb branch of the mass-deformed superconformal Lagrangian theory with gauge group $G_2$ and four fundamental hypermultiplets. Notably, our analysis proceeds by using various geometric constraints to bootstrap the data of the theory, and makes no explicit reference to the Seiberg-Witten curve. We conjecture a corresponding VOA and check that the vacuum character satisfies a linear modular differential equation of fourth order. We also propose an identification with existing class $\mathcal{S}$ constructions.
