General instanton counting and 5d SCFT
Chiung Hwang (Department of Physics & Postech Center for Theoretical Physics (PCTP), Postech, Pohang, 790-784, South Korea); Joonho Kim (Department of Physics and Astronomy & Center for Theoretical Physics, Seoul National University, Seoul, 151-747, South Korea); Seok Kim (Department of Physics and Astronomy & Center for Theoretical Physics, Seoul National University, Seoul, 151-747, South Korea); Jaemo Park (Department of Physics & Postech Center for Theoretical Physics (PCTP), Postech, Pohang, 790-784, South Korea)
Instanton partition functions of 5d N = 1 $$ \mathcal{N}=1 $$ gauge theories are Witten indices for the ADHM gauged quantum mechanics with (0, 4) SUSY. We derive the integral contour prescriptions for these indices using the Jeffrey-Kirwan method, for gauge theories with hypermultiplets in various representations. The results can be used to study various 4d/5d/6d QFTs. In this paper, we study 5d SCFTs which are at the UV fixed points of 5d SYM theories. In particular, we focus on the Sp( N ) theories with N f ≤ 7 fundamental and 1 antisymmetric hypermultiplets, living on the D4-D8-O8 systems. Their superconformal indices calculated from instantons all show E N f + 1 $$ {E_N}_{{}_f+1} $$ symmetry enhancements. We also discuss some aspects of the 6d SCFTs living on the M5-M9 system. It is crucial to understand the UV incompleteness of the 5d SYM, coming from small instantons in our problem. We explain in our examples how to fix them. As an aside, we derive the index for general gauged quantum mechanics with (0 , 2) SUSY.
