Towards a satisfactory microscopic description of 21+ g factors.

We investigate the possibility that microscopic boson [ital g] factor estimates may require revision and consider the impact on 2[sub 1][sup +] [ital g] factors of the difference [epsilon][sub [ital v]] between the neutron and proton [ital d] boson energies found typically in microscopic evaluations of interacting boson model parameters. We recalculate microscopic estimates for both [ital d] and [ital g] boson [ital g] factors, this time using the similarity-transformed Dyson boson mapping approach. Modulo more pronounced variation at the beginning and end of shells, our results confirm previous estimates by other methods. Differences between [ital d] and [ital g] boson factors are too small for the inclusion of [ital g] bosons to have a significant effect on 2[sub 1][sup +] [ital g] factor predictions. Instead, we present qualitative and semiquantitative arguments in support of the contention that [ital microscopic] estimates of [epsilon][sub [ital v]] (taken in conjunction with our microscopic boson [ital g] factors) can, by and large, account for the systematics of 2[sub 1][sup +] [ital g] factors in the [ital Z]=50-to-82 and [ital N]=82-to-126 shells. Detailed calculations for [sup 148]Sm and [sup 154]Sm are consistent with this assertion provided the Majorana interaction strength [xi][sub 2] is negligible. more » Our detailed calculations suggest substantial [ital F]-spin admixtures in the 2[sub 1][sup +] states of [sup 148]Sm (at the 20% level or more) and the members of ground-state band of [sup 154]Sm (9% or so), and point to the existence of a mixed-symmetric [beta] bandhead in [sup 154]Sm at below 2 MeV. « less