The strangeness radius and magnetic moment of the nucleon revisited

We update Jaffeʹs 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 μs = −0.24±0.03 n.m. and rs2 = 0.21±0.03 fm2. The strange formfactor F2s(t) follows a dipole with a cut-off mass of 1.46 GeV, F2s(t) = μs(1 − t2.14GeV2)−2. We also discuss the theoretical uncertainties entering this approach.