Three-body resonances in He-6, Li-6, and Be-6, and the soft dipole mode problem of neutron halo nuclei

Abstract

Using the complex scaling method, the low-lying three-body resonances of ${}^6$He, ${}^6$Li, and ${}^6$Be are investigated in a parameter-free microscopic three-cluster model. In ${}^6$He a 2${}^{+}$, in ${}^6$Li a 2${}^{+}$ and a 1${}^{+}$, and in ${}^6$Be the 0${}^{+}$ ground state and a 2${}^{+}$ excited state is found. The other experimentally known 2${}^{+}$ state of ${}^6$Li cannot be localized by our present method. We have found no indication for the existence of the predicted 1${}^{-}$ soft dipole state in ${}^6$He. We argue that the sequential decay mode of ${}^6$He through the resonant states of its two-body subsystem can lead to peaks in the excitation function. This process can explain the experimental results in the case of ${}^{11}$Li, too. We propose an experimental analysis, which can decide between the soft dipole mode and the sequential decay mode.

REVTEX, Submitted to Phys. Rev. C, 12 pages, 2 postscript figures are available upon request. CALTECH, MAP-166

References in corpus (5)

• The neutron halo of ${}^6$He in a microscopic model
• Nucleon polarization in three-body models of polarized \bbox{^6}Li
• Three-body resonances by complex scaling
• Microscopic description of the beta delayed deuteron emission from \bbox{^6}He
• Localization of shadow poles by complex scaling

Cited by in corpus (30)

• Solar Fusion Cross Sections
• Radioactive decays at limits of nuclear stability
• Pairing anti-halo effect
• S-matrix and R-matrix determination of the low-energy He-5 and Li-5 resonance parameters
• Three-body decay of ${}^6$Be
• Exploration of resonances by analytic continuation in the coupling constant
• Algebraic Model for scattering of three-s-cluster systems. II. Resonances in the three-cluster continuum of 6He and 6Be
• The Be7(p,gamma)B8 cross section and the properties of Be7
• The cluster-core model for halo-structure of light nuclei at the drip lines
• Particle-unstable nuclei in the Hartree-Fock theory
• Dipole excited states in ${}^{11}$Li with complex scaling
• Three-alpha structures in C-12
• Isovector and isoscalar dipole excitations in ${}^9$Be and ${}^{10}$Be studied with antisymmetrized molecular dynamics
• Searching for three-nucleon resonances
• Effects of four-body breakup on 6Li elastic scattering near the Coulomb barrier
• Electric dipole response of ${}^6$He: Halo-neutron and core excitations
• Deduction of the quantum numbers of low-lying states of 6-nucleon systems based on symmetry
• Sensitivity of three-body decays to the reactions mechanism and the initial structure by example of 6Be
• Large-space cluster model calculations for the He3(He3,2p)He4 and H3(H3,2n)He4 reactions
• Analytical E1 strength functions of two-neutron halo nuclei: the 6-He example
• Analytical E1 strength functions of two-neutron halo nuclei: 11-Li and 14-Be
• Four-body DWBA calculations of the Coulomb breakup of 6He
• Three-body properties of low-lying ${}^{12}$Be resonances
• S-matrix studies of resonances in A=3,4,5,6, and 12 nucleon systems
• Comment on ``Large-space shell-model calculations for light nuclei''
• Universality of excited three-body bound states in one dimension
• Structure of A=6 Nuclei: ${}^{6}He$, ${}^{6}Li$ and ${}^{6}Be$
• Origin of three-body resonances
• Study of resonance states of ${}^{11}$Be with isospectral bound state microscopic potential
• Improved convergence of scattering calculations in the oscillator representation