Nuclear rotation in the continuum

Abstract : Atomic nuclei often exhibit collective rotational-like behavior in highly excited states, well above the particle emission threshold. What determines the existence of collective motion in the continuum region, is not fully understood. In this work, by studying the collective rotation of the positive-parity deformed configurations of the one-neutron halo nucleus $^{11}$Be, we assess different mechanisms that stabilize collective behavior beyond the limits of particle stability. To solve a particle-plus-core problem, we employ a coupled-channel formalism and the Berggren single-particle ensemble, which explicitly contains bound states, narrow resonances, and the scattering space. We study the valence-neutron density in the intrinsic rotor frame to assess the validity of the adiabatic approach as the excitation energy increases. We demonstrate that collective rotation of the ground band of $^{11}$Be is stabilized by (i) the fact that the $\ell=0$ one-neutron decay channel is closed, and (ii) the angular momentum alignment, which increases the parentage of high-$\ell$ components at high spins; both effects act in concert to decrease decay widths of ground-state band members. This is not the case for higher-lying states of $^{11}$Be, where the $\ell=0$ neutron-decay channel is open and often dominates.
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Contributor : Michel Lion <>
Submitted on : Tuesday, September 29, 2015 - 8:18:28 AM
Last modification on : Wednesday, August 7, 2019 - 2:32:05 PM

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K. Fossez, W. Nazarewicz, Y. Jaganathen, N. Michel, M. Ploszajczak. Nuclear rotation in the continuum. Physical Review C, American Physical Society, 2016, 93 (1), pp.011305(R). ⟨10.1103/PhysRevC.93.011305⟩. ⟨in2p3-01206405⟩

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