Role of octupole shape degree of freedom in neutron-rich odd-mass xenon isotopes

Influences of the octupole shape degree of freedom on low-energy spectra of neutron-rich odd-mass xenon isotopes are studied within the interacting boson-fermion model that is based on the nuclear density functional theory. The interacting-boson Hamiltonian describing low-energy quadrupole and octupole collective states of the even-even nuclei $^{140,142,144}\mathrm{Xe}$, single-particle energies, and occupation probabilities for an unpaired neutron in the odd-mass nuclei $^{141,143,145}\mathrm{Xe}$, are determined based on the axially symmetric quadrupole-octupole deformation-constrained self-consistent mean-field calculations with a choice of the energy density functional and pairing interaction. Strength parameters of the boson-fermion interactions are empirically determined to reproduce a few low-lying levels of each odd-mass nucleus. The mean-field calculation predicts for $^{142}\mathrm{Xe}$ a potential energy surface that is notably soft in the octupole deformation with a nonzero octupole global minimum. The octupole correlations are shown to be relevant in positive-parity excited states of $^{143,145}\mathrm{Xe}$.