Connecting the Pygmy Dipole Resonance to the neutron skin

Abstract

We study the correlation between the neutron skin development and the low-energy dipole response associated with the pygmy dipole resonance (PDR) in connection with the properties of symmetry energy. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation by employing three different equations of state in the isovector sector. Together with the giant dipole resonance (GDR) for all studied systems, we identify a PDR collective mode whose energy centroid is very well described by the parametrization E_{PDR}=41 A^{-1/3}. A linear correlation between the energy weighted sum rule (EWSR) associated to PDR and the neutron skin thickness is evidenced. An increase of 15 MeVfm^2 of EWSR, in correspondence to a change of 0.1fm of the neutron skin size, is obtained. We conjecture that different nuclei having close neutron skin sizes will exhaust the same EWSR in the pygmy region. This suggests that a precise experimental estimate of the total EWSR exhausted by the PDR allows the determination of the neutron skin size, constraining the slope parameter of the symmetry energy.

8 pages, 7 figures (new figures added)

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Cited by in corpus (15)

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• Extended Skyrme interactions for transport model simulations of heavy-ion collisions
• Dipole response in neutron-rich nuclei with new Skyrme interactions
• Interplay between low-lying isoscalar and isovector dipole modes: a comparative analysis between semi-classical and quantum approaches
• Isoscalar and neutron modes in the E1 spectra of Ni isotopes and the relevance of shell effects and the continuum
• Theoretical predictions of experimental observables sensitive to the symmetry energy: Results of the SMF transport model
• Low-energy quadrupole states in neutron-rich tin nuclei
• Nuclear collective dynamics in transport model with the lattice Hamiltonian method
• Nuclear excitations within microscopic EDF approaches : pairing and temperature effects on the dipole response
• Nuclear skin and the curvature of the symmetry energy
• Pre-equilibrium effects in charge-asymmetric low-energy reactions
• Pairing effects on spinodal decomposition of asymmetric nuclear matter
• Effects of pairing correlations on the neutron skin thickness and the symmetry energy
• Pygmy resonances: what's in a name?
• Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms