Octupole deformation in 142,143Ba and 144Ce: new band structures in neutron-rich Ba-isotopes

Abstract New, high spin band structures are established for the neutron-rich nuclei 142,143,145,147 Ba, and 144 Ce, and levels of 144,146 Ba extended to higher spins from the study of γ-γ and γ-γ-γ coincidence studies in spontaneous fission. Alternating parity sequences connected by strong electric dipole transitions are identified in 142,143 Ba and 144 Ce but not in 145,147 Ba to confirm theoretical predictions of stable octupole deformation for N = 86.