Structure of the isovector dipole resonance in neutron-rich 60 Ca nuclei and direct decay from pygmy resonance

Abstract

The structure of the isovector dipole resonance in neutron-rich calcium isotope, 60Ca, has been investigated by implementing a careful treatment of the differences of neutron and proton radii in the continuum random phase approximation (RPA). The calculations have taken into account the current estimates of the neutron skin. The estimates of the escape widths for direct neutron decay from the pygmy-dipole resonance (PDR) were shown rather wide, implicating a strong coupling to the continuum. The width of the giant-dipole resonance (GDR) was evaluated, bringing on a detailed discussion about its microscopic structure.