Iskra, ŁukaszMarginean, R.Bottoni, S.N. MargineanFornal, BogdanLeoni, S.G. ColoL. StanR. BorceaM. BoromizaS. C˘alinescuCieplicka-Oryńczak, N.C. Clisu-StanC. CostacheF.C.L. CrespiD. FilipescuN. FloreaI. GheorgheA. IonescuR. LicaC. MihaiR.E. MihaiC.R. NitaS. PascuC. PetroneS. TomaA. TurturicaS. Ujeniuc2025-01-292025-01-292024-12-13PHYSICAL REVIEW C 110, 064312 (2024)https://rifj.ifj.edu.pl/handle/item/433https://doi.org/10.1103/PhysRevC.110.064312The B(E3) transition strengths in 90Zr and 91Zr isotopes were determined based on the half-life measurements of the first 3− and (11/2)− states, i.e., T1/2 = 7.8(16) ps and 500(16) ps, respectively. The plunger method and fast-timing techniques were employed. The B(E3) values of 16(3) and 20.5(7) W.u. for 90Zr and 91Zr were derived, pointing to a sizable octupole collectivity in both cases. The 90Zr value complements the systematics of the octupole strength in even-even Zr isotopic chain, revealing a smooth trend between A = 90 and 96, which is in agreement with the pattern of octupole strength predicted by quasiparticle random phase approximation calculations. In 91Zr, the hybrid configuration mixing model describes the (11/2)− low-energy strength in terms of a coupling of the unpaired neutron with the 3− octupole excitation of the 90Zr core, predicting a slight decrease of octupole strength which is in contrast with the experimental result. This suggests a more complex structure for the (11/2)− state in 91Zr than predicted by the weak-coupling limit.Attribution 4.0 InternationalOther