The ^154Sm nucleus, which has long been regarded as a typical quantum system exhibiting axial symmetry, has been recently suggested to exhibit a small degree of triaxiality by Otsuka et al. . This small triaxiality was recently observed using the γ decay of the ^154Sm isovector giant dipole resonance. Thus further studying this small triaxiality is very necessary for understanding the nature of the collectivity in nuclei. In this paper, the rigid triaxiality in ^154Sm is investigated using the newly proposed SU3-IBM theory. If the irreducible representation (irrep) of the ground state is (18, 2) in the SU (3) symmetry limit, the new model can effectively reproduce the experimental data of ^154Sm, showing good agreements with realistic energy spectra, B (E2) values, and quadrupole moments. This result further confirms the vality of the SU3-IBM for the description of the rigid triaxiality in realistic nuclei, and reveals the SU (3) dominance of the collectivity motions in nuclei.
Zhou et al. (Fri,) studied this question.