Critical assessment of interacting boson model wavefunctions from measured gyromagnetic ratios of lowest eigenstates in even Os isotopes

The gyromagnetic ratios of the low-lying levels in the even 188-192Os isotopes were measured. Of particular import, the ratios g(22+)/g(21+) were found to be 1.45 +- 0.18, 0.99 +- 0.14, and 0.72 +- 0.06 in 188Os, 190Os, and 192Os, respectively. Although the E2 observables in these nuclides are accommodated quite well in interacting boson model descriptions (IBM-1 and -2), both formulations fail to concurrently account for either the intra-nucleus or mass-dependent g-factor variations of the lowest eigenstates in these Os isotopes. (author)