Critical assessment of interacting boson model wave functions 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(2⁺₂)/g(2⁺₁) 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 IBM-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.