Identification of high- K rotation in Ba130 : Testing the consistency of electromagnetic observables

Abstract

The band built on the K π = 8 − , T 1/2 = 9.4 ms isomer of 130 Ba has been identified, filling the gap in the systematics of the dipole bands built on the 8 − isomers in the N = 74 isotones from 128 Xe to 138 Gd. The use of the GALILEO array in conjunction with its ancillaries EUCLIDES and Neutron Wall, helped to firmly place the newly identified transitions on top of the long-lived isomer. The extracted g K and g R gyromagnetic factors are in agreement with the 7/2 + [404] ⊗ 9/2 − [514] two-neutron Nilsson configuration. Particle-rotor model calculations give an understanding of the limited degree of K mixing. The experimental information on the K π = 8 − isomer of 130 Ba is now the most complete among the K isomers of the N = 74 isotones.

High- K three-quasiparticle isomers in the proton-rich nucleus Nd129

“…If the δ values are positive, the (g K − g R )/Q 0 values are also positive for a prolate shape [41]. To estimate g K we can adopt a smaller gyromagnetic factor of g R = 0.3 than the rotational approximation g R = Z/A = 0.46, as suggested by that recently observed experimentally for the 8 − high-K isomer in 130 Ba, for which g R = 0.278 (15) has been extracted instead of g R = Z/A = 0.43 [42]. We can also adopt an intrinsic quadrupole mo-ment of Q 0 = 5.5 eb corresponding to an axially symmetric prolate shape with a deformation of β 2 = 0.3, as suggested by the calculations.…”