What Do We Know About the Strange Magnetic Radius?
  We analyze the q^2-dependence of the strange magnetic form factor, \GMS(q^2), using heavy baryon chiral perturbation theory (HBChPT) and dispersion relations. We find that in HBChPT a significant cancellation occurs between the O(p^2) and O(p^3) loop contributions. Consequently, the slope of \GMS at the origin displays an enhanced sensitivity to an unknown O(p^3) low-energy constant. Using dispersion theory, we estimate the magnitude of this constant, show that it may have a natural size, and conclude that the low-q^2 behavior of \GMS could be dominated by nonperturbative physics. We also discuss the implications for the interpretation of parity-violating electron scattering measurements used to measure \GMS(q^2). 
H.-W. Hammer (1), S.J. Puglia (1), M.J. Ramsey-Musolf (2 and 3),   Shi-Lin Zhu (2) ((1) Ohio State U., (2) Caltech, (3) U. o...