Triaxiality induced monopole-quadrupole-hexadecupole coupling in the isoscalar giant resonances for $^{86}\textrm{Ge}$

Published 7 Jun 2022 in nucl-th | (2206.03030v1)

Abstract: The isoscalar giant resonances for $^{{86}\textrm{Ge}$} are studied by the quasiparticle finite amplitude method based on the covariant density functional theory. In addition to the well-known monopole-quadrupole coupling that splits the isoscalar giant monopole resonance in axially deformed nuclei, a monopole-quadrupole-hexadecupole coupling is identified in the triaxially deformed nucleus $^{{86}\textrm{Ge}$,} leading to the emergence of a distinct resonance peak at the low energy side of the isoscalar monopole strength function. The transition density of the triaxiality induced resonance peak shows a strong interplay among monopole, quadrupole, and hexadecupole vibrations. The resonance peak responses to monopole, quadrupole, and hexadecupole perturbations simultaneously, which could be regarded as a fingerprint of the triaxiality in $^{{86}\textrm{Ge}$.}