Different triaxial shapes in the energy spectra of 154Sm

The 154 Sm 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 through the γ decay of the 154 Sm 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 154 Sm is investigated using the newly proposed SU3-IBM theory. The fitting results can effectively reproduce the experimental data of 154 Sm, showing good agreement with realistic energy spectra, B(E2) values, and quadrupole moments, which indicates the emergence of the different triaxial shapes in the energy spectra. These results further confirm the validity of the SU3-IBM for the description of the rigid triaxiality in realistic nuclei and reveal the SU(3) dominance of the collectivity motions in nuclei.