Nonperturbative nonrenormalization theorem for supersymmetric QCD

We show that no radiative masses are acquired by the Goldstone pion supermultiplet in supersymmetric QCD. Thus, in contrast to ordinary QCD, the mass difference msub(π)2+-msub(π)20 remains zero even after electromagnetism is turned on. Bound state Goldstone supermultiples obey a nonrenormalization theorem analogous to that obeyed by elementary chiral superfields. (orig.)