A note on W symmetry of N=2 gauge theory

Abstract

The AGT correspondence indicates $\mathcal{N}=2$ gauge theory possesses of W algebra symmetry. We study how the conformal block of Toda CFT gives the expectation value of Casimir operators of gauge theory. The $A_2$ Toda CFT with $W_3$ symmetry is taken as the main example.

v1, 16pp; v2, references added, typos and several numerical factors corrected