Pairing in the continuum: the quadrupole response of the Borromean nucleus 6He

Abstract

The ground state and low-lying continuum states of 6He are found within a shell model scheme, in a basis of two-particle states built out of continuum p-states of the unbound 5He nucleus, using a simple pairing contact-delta interaction. This accounts for the Borromean character of the bound ground state, revealing its composition. We investigate the quadrupole response of the system and we put our calculations into perspective with the latest experimental results. The calculated quadrupole strength distribution reproduces the narrow 2+ resonance, while a second wider peak is found at about 3.9 MeV above the g.s. energy.

5 pages, 5 figures

References in corpus (5)

• Complex coupled-cluster approach to an ab-initio description of open quantum systems
• Resonances of 7He in the complex scaling method
• ${}^4\mathrm{He}$+$n$+$n$ continuum within an ab initio framework
• Effective Interaction Techniques for the Gamow Shell Model
• Electric dipole response of ${}^6$He: Halo-neutron and core excitations

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• Deformation, halo, and bubble structure: A paradigm shift of exotic phenomena in light to medium mass nuclei
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• Resonances and collisional properties of neutron-rich helium isotopes in the adiabatic hyperspherical representation