Hierarchies of RG flows in 6d (1, 0) massive E-strings

We extend the analysis of [9] to the 6d (1, 0) SCFTs known as massive E-string theories, which can be engineered in massive Type IIA with 8 − n0 < 8 D8-branes close to an O8− (or O8∗if n0 = 8, 9). For each choice of n0 = 1, . . . , 9 the massive E1+(8−n0)-strings (including the more exotic E˜1 and E0) are classified by constrained E8 Kac labels, i.e. a subset of Hom(Zk, E8), from which one can read off the flavor subalgebra of E1+(8−n0) of each SCFT. We construct hierarchies for two types of Higgs branch RG flows: flows between massive theories defined by the same n0 but different labels; flows between massive theories with different n0. These latter flows are triggered by T-brane vev’s for the right SU factor of the SCFT global symmetry, whose rank is a function of both k and n0, a situation which has so far remained vastly unexplored.