Relativistic Hartree-Bogoliubov model with density-dependent meson-nucleon couplings

TLDR

The effective Lagrangian incorporates phenomenological density dependence for the σ, ω, and ρ meson‑nucleon vertices, tuned to nuclear matter and finite‑nucleus properties. The study extends the relativistic Hartree‑Bogoliubov model to include density‑dependent meson‑nucleon couplings. Using the density‑dependent interaction DD‑ME1, the authors model pairing with a finite‑range Gogny force, compute equations of state for symmetric and asymmetric nuclear matter, analyze ground‑state properties of Sn and Pb isotopic chains, and evaluate parity‑violating elastic electron scattering on Pb and Sn nuclei with a relativistic optical model that accounts for Coulomb distortion. Self‑consistent RHB calculations with DD‑ME1 agree with experimental data and outperform earlier RHB models with nonlinear self‑interactions, while the calculated parity‑violating asymmetries provide insight into neutron density distributions.

Abstract

The relativistic Hartree-Bogoliubov (RHB) model is extended to include density dependent meson-nucleon couplings. The effective Lagrangian is characterized by a phenomenological density dependence for the $\sigma$, $\omega$ and $\rho$ meson-nucleon vertex functions, adjusted to properties of nuclear matter and finite nuclei. Pairing correlations are described by the pairing part of the finite range Gogny interaction. The new density-dependent effective interaction DD-ME1 is tested in the analysis of the equations of state for symmetric and asymmetric nuclear matter, and of ground-state properties of the Sn and Pb isotopic chains. Results of self-consistent RHB calculations are compared with experimental data, and with results previously obtained in the RHB model with non-linear self-interactions, as well as in the density dependent relativistic hadron field (DDRH) model. Parity-violating elastic electron scattering on Pb and Sn nuclei is calculated using a relativistic optical model with inclusion of Coulomb distortion effects, and the resulting asymmetry parameters are related to the neutron ground-state density distributions.