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 − n 0 < 8 D8-branes close to an O8 − (or O8 * if n 0 = 8 , 9). For each choice of n 0 = 1 , … , 9 the massive E_1+(8-n_0) -strings (including the more exotic ∼E_1 and E 0 ) are classified by constrained E 8 Kac labels, i.e. a subset of Hom(ℤ k , E 8 ), from which one can read off the flavor subalgebra of E_1+(8-n_0) of each SCFT. We construct hierarchies for two types of Higgs branch RG flows: flows between massive theories defined by the same n 0 but different labels; flows between massive theories with different n 0 . 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 n 0 , a situation which has so far remained vastly unexplored.