Symmetry limits of the IBM-3 model with good s and d boson isospins

In addition to the Osd(18) ⊃ Od(15) ⊕ OTs(3) limit identified recently by Ginocchio, the IBM-3 model, which is relevant for proton rich nuclei with N ∼ Z, admits two other symmetry limits (called [Ud(5) ⊗ UTd(3)] ⊕ UTs(3) and [Ud(15) ⊃ Od(15)] ⊕ UTs(3) limits) with good s and d boson isospins. These two symmetry limits preserve s and d boson numbers ns and nd and the limit with Od(15) has α-particle like correlations. For T = 0 states with boson number N even, spectra and E2 transition strengths show that the states with nd ≥ 2 carry signatures of isospin compared to the spherical IBM-1 U(5) limit states. The two symmetry limits differ from the Osd(18) ⊃ Od(15) ⊕ OTs(3) limit in many respects.