Chiral Symmetry and the Nucleon ’ s Vector Strangeness Form Factors

The nucleon’s strange-quark vector current form factors are studied from the perspective of chiral symmetry. It is argued that chiral perturbation theory cannot yield a prediction for the strangeness radius and magnetic moment. Arrival at definite predictions requires the introduction of additional, modeldependent assumptions which go beyond the framework of chiral perturbation theory. A variety of such model predictions is surveyed, and the credibility of each is evaluated. The most plausible prediction appears in a model where the unknown chiral counterterms are identified with t-channel vector meson exchange amplitudes. The corresponding prediction for the mean square Dirac strangeness radius is 〈r2 s〉 = 0.24 fm2, which would be observable in up-coming semileptonic determinations of the nucleon’s strangeness form factors. 11.30.Rd, 12.40.-y, 14.20.Dh Typeset using REVTEX On leave from the Department of Physics, Old Dominion University, Norfolk, VA 23529 USA