The Influence of the Two-Body Spin-Orbit Interaction on Effective Charge

Abstract

Valence particles normally carry an effective charge larger than their bare charge for electric transitions, due to the attractive nuclear interaction. However for the highest multipolarity transitions the particles have enough momentum that the two-body spin-orbit force can also play a substantial role. In the case of the E6 f_7/2→f_7/2 effective charge, the spin-orbit interaction interferes with the central interaction and yields a correction to the proton effective charge close to zero. This is consistent with a recent calculation of proton scattering in the g_9/2 shell, which showed that the spin-orbit interaction dominated the central interaction for L=8.¹⁾ Our calculation fails to account for a recent experimental result in the f_7/2 shell²⁾, which requires an effective charge of magnitude 0.3-0.4³⁾.