Supersymmetric QCD: Exact Results and Strong Coupling

Understand

We revisit two longstanding puzzles in supersymmetric gauge theories.

• The first concerns the question of the holomorphy of the coupling, and related to this the possible definition of an exact (NSVZ) beta function.
• The second concerns instantons in pure gluodynamics, which appear to give sensible, exact results for certain correlation functions, which nonetheless differ from those obtained using systematic weak coupling expansions.
• For the first question, we extend an earlier proposal of Arkani-Hamed and Murayama, showing that if their regulated action is written suitably, the holomorphy of the couplings is manifest, and it is easy to determine the renormalization scheme for which the NSVZ formula holds.