Shapes, softness, and nonyrast collectivity in 186W

Nonyrast, excited states in neutron-rich W-186 were populated via inelastic-scattering reactions using beams of Xe-136 nuclei accelerated to 725 and 800 MeV. Levels populated in the reactions were investigated via particle-lambda coincidence techniques using the Gammasphere array of high-purity germanium detectors and the compact heavy-ion counter, CHICO2. The K-pi = 2(+) (gamma), K-pi = 0(+) and K-pi = 2(-) (octupole) rotational side bands were extended to spins 14 (h) over bar, 12 (h) over bar, and 13 (h) over bar, respectively. A staggering pattern observed in the energies of levels in the K-pi = 2(+) band was found to be consistent with a potential that gets softer to vibration in the gamma degree of freedom with increasing spin. The odd-even staggering of states in the K-pi = 2(-) band was found to exhibit a phase opposite to that seen in the. band; an effect most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in 186W.

Automated summary

Excited states in neutron-rich W-186 were populated via inelastic-scattering reactions using Xe-136 beams accelerated to 725 and 800 MeV. Different rotational side bands were extended to various spins, showing consistency with potential softening to vibration with increasing spin. Odd-even staggering of states in the K-pi = 2(-) band exhibited a phase opposite to that seen in the K-pi = 2(+) band, possibly due to Coriolis coupling.