The Strangeness Radius and Magnetic Moment of the Nucleon Revisited

Abstract

We update Jaffe's estimate of the strange isoscalar radius and magnetic moment of the nucleon. We make use of a recent dispersion--theoretical fit to the nucleon electromagnetic form factors and an improved description of symmetry breaking in the vector nonet. We find ${\mu }_s=-0.24\pm 0.03$~n.m. and $r_s^2=0.21\pm 0.03$~fm${}^2$. The strange formfactor $F_2^s(t)$ follows a dipole with a cut--off mass of 1.46~GeV, $F_2^s(t)={\mu }_s(1-t/2.14{\mathrm{GeV}}^2{)}^{-2}$. These numbers should be considered as upper limits on the strange vector current matrix--elements in the nucleon.

Comments: 8 pp, LaTeX, uses epsf, 1 figure in separate file