Chern-Simons-Trinion Theories: One-form Symmetries and Superconformal Indices

A bstract We study 3d theories containing $$ \mathcal{N} $$ N = 3 Chern-Simons vector multiplets coupled to the SU( N ) 3 flavour symmetry of 3d T N theories with Chern-Simons levels k 1 , k 2 and k 3 . It was formerly pointed out that these theories flow to infrared SCFTs with enhanced $$ \mathcal{N} $$ N = 4 supersymmetry when 1 /k 1 + 1 /k 2 + 1 /k 3 = 0. We examine superconformal indices of these theories which reveal that supersymmetry of the infrared SCFTs may get enhanced to 4 ≤ $$ \mathcal{N} $$ N ≤ 6 if such a condition is satisfied. Moreover, even if the Chern-Simons levels do not obey the aforementioned condition, we find that there is still an infinite family of theories that flows to infrared SCFTs with $$ \mathcal{N} $$ N = 4 supersymmetry. The ’t Hooft anomalies of the one-form symmetries of these theories are analysed. As a by-product, we observe that there is generally a decoupled topological sector in the infrared. When the infrared SCFTs have $$ \mathcal{N} $$ N ≥ 4 supersymmetry, we also study the Higgs and Coulomb branch limits of the indices which provide geometric information of the moduli space of the theories in question in terms of the Hilbert series.