Mass dependence of effective charges in the interacting-boson model

The mass dependence of the E2-boson effective charges in the interacting-boson model is tested by comparison with measurements of B(E${2;0}_1^{+}$→$2_1^{+}$) for ${}_{}{}^{142}{}_{}{}^{}$,144,146,148,15 ${}_{}{}^0{}_{}{}^{}\mathrm{Nd}$. This mass dependence originates from g-boson renormalization effects. The magnitude of this renormalization, as required to reproduce experiment, is consistent with an earlier estimate based on the renormalizations of the single boson energies. The proton effective charge is found to be larger than the neutron effective charge, in agreement with the shell model, but in contrast to an earlier report.