Chiral ring of Sp(N) and SO(N) supersymmetric gauge theory in four dimensions

The chiral ring of classical supersymmetric Yang-Mills theory with gauge group Sp(N) or SO (N) is computed, extending previous work (of Cachazo, Douglas, Seiberg, and the author) for SU(N). The result is that, as has been conjectured, the ring is generated by the usual glueball superfield S ∼ Tr W_αW^α with the relation S^h = 0, h being the dual Coxeter number. Though this proposition has important implications for the behavior of the quantum theory, the statement and (for the most part) the proofs amount to assertions about Lie groups with no direct reference to gauge theory.