Spectral line shape of exotic nuclei

Abstract

The quadrupole strength function of 28 O is calculated making use of the SIII interaction, within the framework of continuum-RPA and taking into account collisions among the nucleons (doorway coupling). The centroid of the giant resonance is predicted at ≈ 14 MeV, that is much below the energy expected for both isoscalar and isovector quadrupole resonances in nuclei along the stability valley. About half of this width arises from the coupling of the resonance to the continuum and about half is due to doorway coupling. This result is similar to that obtained in the study of giant resonances in light, β-stable nuclei, and shows the lack of basis for the expectation, entertained until now in the literature, that continuum decay was the main damping mechanism of giant resonances in halo nuclei [1].

Continuum linear response in coordinate space Hartree–Fock–Bogoliubov formalism for collective excitations in drip-line nuclei

“…The dynamical effect is rather related to effects of the quadrupole pairing that has been discussed in connection with the low-lying quadrupole mode in stable nuclei. energy weighted sum [fm 4 MeV] Fig.5). Namely the pairing is taken into account only in the static HFB mean-field.…”

“…Since the method itself is a general framework to describe normal modes of excitation built on a reference state given by mean-field approximations [1], it is advantageous to, rather than very light drip-line nuclei such as 11 Li, heavier systems which will be studied in future experiments. Previous works in this direction have analyzed the giant resonances and the threshold neutron strength in exotic nuclei with closed shell configurations [2][3][4] with use of the continuum linear response theory formulated in the coordinate space [5,6]. However, to explore more systematically nuclei with open shell configurations, the theory has to be extended so as to take into account the pairing correlation, which may play essential roles especially for low-lying collective excitations.…”

Collective Excitations and Pairing Effects in Drip-Line Nuclei

“…Indeed the continuum RPA theory in the coordinate-space representation 1), 2) has played major roles so far since it can describe the continuum states crucial for nuclei near drip-line. 3) - 5) The pairing correlation is another key feature of drip-line nuclei. 6) - 8) To treat the coupling of the continuum states as well as the density dependence of the pairing correlation, the Hartree-Fock-Bogoliubov (HFB) theory formulated in the coordinate-space representation 6), 9) has been developed while the conventional BCS approximation has inherent deficiency.…”

Softening the long-wavelength electromagnetic response of finite quantal systems

“…A possible candidate of halo nucleus, although not yet found, is the system 28 8 O 20 [84,87,88,91]. A possible candidate of halo nucleus, although not yet found, is the system 28 8 O 20 [84,87,88,91].…”