Shapes, softness, and nonyrast collectivity in $^{186}\mathrm{W}$

International audienceNonyrast, excited states in neutron-rich W186 were populated via inelastic-scattering reactions using beams of Xe136 nuclei accelerated to 725 and 800 MeV. Levels populated in the reactions were investigated via particle-γ coincidence techniques using the Gammasphere array of high-purity germanium detectors and the compact heavy-ion counter, CHICO2. The Kπ=2+ (γ), Kπ=0+ and Kπ=2− (octupole) rotational side bands were extended to spins 14ℏ, 12ℏ, and 13ℏ, respectively. A staggering pattern observed in the energies of levels in the Kπ=2+ band was found to be consistent with a potential that gets softer to vibration in the γ degree of freedom with increasing spin. The odd-even staggering of states in the Kπ=2− band was found to exhibit a phase opposite to that seen in the γ band; an effect most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in W186