Several rotational bands have been populated to high spin in Cs127 following the Sn120(11B,4n) reaction. Rotational bands built on low-lying proton g7/2, d5/2, and g9/2 (hole) orbitals, and the unique-parity h11/2 orbital were observed and identified. For the g9/2 (hole) case, both signatures were seen in a strongly coupled I=1 band, while for the other cases, decoupled I=2 bands were observed with strong in-band quadrupole transitions. Through comparisons with cranked-shell-model calculations, these band structures are understood to be associated with a prolate (0°) deformed nuclear shape. At frequencies above Latin small letter h with stroke=0.3 MeV, the rotational alignment of a pair of h11/2 neutrons was observed for each of the h11/2, g7/2, and d5/2 bands. This neutron alignment is predicted to drive the nuclear core away from a prolate shape towards the collectively rotating oblate (=-60°) shape. Changes in the measured signature splittings for the bands below and above the alignment are consistent with the shape changes.
ASJC Scopus subject areas
- Nuclear and High Energy Physics