Testing our understanding of SCFTs: a catalogue of rank-2 $$ \mathcal{N} $$ = 2 theories in four dimensions

In this paper we begin mapping out the space of rank-2 $$ \mathcal{N} $$ N = 2 superconformal field theories (SCFTs) in four dimensions. This represents an ideal set of theories which can be potentially classified using purely quantum field-theoretic tools, thus providing a precious case study to probe the completeness of the current understanding of SCFTs, primarily derived from string theory constructions. Here, we collect and systematize a large amount of field theoretic data characterizing each theory. We also provide a detailed description of each case and determine the theories’ Coulomb, Higgs and Mixed branch stratification. The theories naturally organize themselves into series connected by RG flows but which have gaps suggesting that our current understanding is not complete.