Two-body interaction currents and nuclear magnetic moments

Abstract

The meson-theoretical approach to nuclear interaction currents is considered in the one-meson exchange approximation. Results are presented for two models of charge-symmetric πN coupling: the γ 5 model and the static model. The effect of interaction currents on the nuclear dipole magnetic moment of odd-mass-nuclei with jj closed-shells plus (or minus) one nucleon is calculated within the framework of the pure spherical shell model. For nuclei with a closed ls core ( 15N, 17O, 39K and 41Ca), first-order perturbation corrections are also taken into account. The contribution of interaction magnetic moments is found to be generally small in magnitude, but to depend strongly on the angular momentum of the nucleus; the net effect is a translation of both Schmidt lines, upwards for odd-proton nuclei and downwards for odd-neutron nuclei. For 209Bi, the correction is 0.5 nucleon magneton. The magnetic moment associated with the two-body spin-orbit interaction is also calculated: it accounts for approximately 1 5 of the contribution from the one-body spin-orbit force.