Low-energy theorems are derived for the scattering of isovector-vector bosons on nucleons, the external boson mass having been continued to zero. The basic technique is that invented by Low to deal with the ordinary or Abelian Compton effect. These theorems are combined with forward-dispersion relations to yield two magnetic-moment sum rules. One of these sum rules is that derived by Cabibbo and Radicati; the other—to the best of the author's knowledge—is new. Neither sum rule admits of even approximate saturation by the (3,3) resonance.

• Received 9 June 1966

DOI:https://doi.org/10.1103/PhysRev.150.1276