Some Implications of the Bootstrap Model for the Electromagnetic Properties of Baryons

Abstract

If baryons are baryon-meson bound states, their electromagnetic (EM) mass splittings result from (i) long-range EM forces between their constituents; (ii) EM mass splittings of their constituents; (iii) charge-dependent corrections (short-range) to the strong forces. The model implies many self-consistency conditions, some of which we exploit to estimate the total baryon magnetic moments in terms of the orbital $g$ values of the mesons, and the baryon EM splittings in terms of Coulomb and magnetic energies and of the observed meson EM splittings. The baryons are treated as static, and effects of type (iii) are assumed not to be crucial. Though our assumptions may constitute a poor model of reality, the results of the model follow immediately from its physics, and should be a reliable qualitative guide to the output of correct but more sophisticated calculations based on similar physical ideas. Comparison with experiment shows that it is essential to include strange particles even when considering the nucleons, and that the motion is not essentially relativistic. Agreement is satisfactory for splittings and for the isovector moment, and less so for the isoscalar moments. We make some comments on alternative approaches to these problems.