Collective excitations induced by pairing anti-halo effect
Heavy Ion Nuclear Physics Laboratory, RIKEN, 351-0198, Japan
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Accepted: 11 March 2005
Published online: 24 June 2005
We emphasize a special interplay of loosely-bound neutrons with small orbital angular momentum ℓ and self-consistent pairing correlations for low-lying collective vibrational excitations in neutron drip line nuclei. Change of the spatial structure in quasiparticle wave functions by self-consistent pairing correlations leads to the broad localization of two-quasiparticle states with low-ℓ neutrons. We show that the broad localization can cause the enhancement of the low-lying collectivity. By performing HFB plus quasiparticle random phase approximation (QRPA) calculation for the first 2+ states in neutron rich Ni isotopes, the unique role of self-consistent pairing correlations is examined. Finally we make a comment on deformation effects for low-lying vibrational excitations in neutron drip line nuclei.
PACS: 21.10.Re Collective levels – / 21.60.Ev Collective models – / 21.60.Jz Hartree-Fock and random-phase approximations –
© Società Italiana di Fisica and Springer-Verlag, 2005