Identification of a dipole band above the Iπ = 31/2- isomeric state in 189Pb
Hodge, D., Cullen, D. M., Taylor, M. J., Procter, M. G., Nieminen, P., Grahn, T., . . . Uusitalo, J. (2015). Identification of a dipole band above the Iπ = 31/2- isomeric state in 189Pb. Physical Review C, 92 (5), 054312. doi:10.1103/PhysRevC.92.054312
Published inPhysical Review C
© 2015 American Physical Society. Published in this repository with the kind permission of the publisher.
A dipole band of six transitions built upon a firmly established I π = 31/2− isomeric state has been identified in 189Pb using recoil-isomer tagging. This is the lightest odd-mass Pb nucleus in which a dipole band is known. The dipole nature of the new transitions has been confirmed through angular-intensity arguments. The evolution of the excitation energy and the aligned-angular momentum of the states in the new dipole band are compared with those of dipole bands in heavier, odd-mass lead isotopes. This comparison suggests that the new band in 189Pb is based upon a π[s−2 1/2h9/2i13/2]11− ⊗ ν[i −1 13/2+ ]13/2+ configuration. However, the increased aligned-angular momentum in 189Pb may suggest evidence for a reduced repulsive proton/neutron-hole interaction compared to dipole bands in the heavier mass isotopes.