Instanton operators and symmetry enhancement in 5d supersymmetric gauge theories

TL;DR

This paper investigates the conditions under which five-dimensional supersymmetric gauge theories experience symmetry enhancement at their ultraviolet fixed points, using analysis of fermionic zero modes around instanton operators.

Contribution

It introduces a straightforward criterion for predicting symmetry enhancement in 5d supersymmetric gauge theories based on fermionic zero mode analysis.

Findings

Provides a criterion for symmetry enhancement in 5d theories.

Connects instanton operator analysis to UV fixed point symmetries.

Suggests possible six-dimensional origins of 5d theories.

Abstract

Supersymmetric gauge theories in five dimensions often exhibit less symmetry than the ultraviolet fixed points from which they flow. The fixed points might have larger flavor symmetry or they might even be secretly six-dimensional theories on S^1. Here we provide a simple criterion when such symmetry enhancement in the ultraviolet should occur, by a direct study of the fermionic zero modes around one-instanton operators.