Dipole response in deformed halo nuclei ${}^{42}\mathrm{Mg}$ and ${}^{44}\mathrm{Mg}$

Abstract

The quasiparticle finite amplitude method based on the deformed relativistic Hartree-Bogoliubov theory in continuum has been developed for the noncharge-exchange multipole response. Taking neutron-rich magnesium isotopes as examples, the isovector electric dipole response, especially in the low-lying region, is studied. It is found that the low-energy dipole strength increases with neutron number and becomes notably enhanced in the predicted deformed halo nuclei ${}^{42}\mathrm{Mg}$ and ${}^{44}\mathrm{Mg}$. In these isotopes, the $K^{\pi }=1^{-}$ states below 3 MeV are dominated by transitions from the ``halo" part of the single-neutron orbitals. Their transition densities reveal a low-frequency, out-of-phase oscillation between the neutron halo and the core. These results provide a microscopic picture for the soft dipole resonance in ${}^{42}\mathrm{Mg}$ and ${}^{44}\mathrm{Mg}$.

References in corpus (9)

• Relativistic Continuum Hartree Bogoliubov Theory for Ground State Properties of Exotic Nuclei
• Exotic modes of excitation in atomic nuclei far from stability
• Constraints on the symmetry energy and on neutron skins from the pygmy resonances in 68Ni and 132Sn
• All the Fun of the FAIR: Fundamental physics at the Facility for Antiproton and Ion Research
• Finite amplitude method for the quasi-particle-random-phase approximation
• Finite Amplitude Method for Charge-Changing Transitions in Axially-Deformed Nuclei
• Halo-induced large enhancement of soft dipole excitation of 11Li observed via proton inelastic scattering
• Finite-amplitude method for collective inertia in spontaneous fission
• Modeling the electric dipole strength of neutron-rich ${}^8$He: Prediction of multineutron collective excitations