Nuclear surface properties in relativistic effective field theory

Abstract

We perform Hartree calculations of symmetric and asymmetric semi-infinite nuclear matter in the framework of relativistic models based on effective hadronic field theories as recently proposed in the literature. In addition to the conventional cubic and quartic scalar self-interactions, the extended models incorporate a quartic vector self-interaction, scalar-vector non-linearities and tensor couplings of the vector mesons. We investigate the implications of these terms on nuclear surface properties such as the surface energy coefficient, surface thickness, surface stiffness coefficient, neutron skin thickness and the spin-orbit force.Comment: 30 pages, 15 figures. Submitted to Nuclear Physics

Versatility of field theory motivated nuclear effective Lagrangian approach

“…That this is indeed the case has been proven in previous works and therefore we shall not attempt to present more results in this respect here. We rather refer the reader to the literature [3,9,10,11,12,13] where it has been shown that the bulk and singleparticle properties of finite nuclei are well described by the E-RMF model with a similar quality to the standard RMF parametrizations, not only for stable isotopes but also for exotic isospin-rich nuclei far from the valley of β stability.…”

“…The truncation of the effective Lagrangian at the first lower orders is validated by the fact that when one includes up to fourth order terms in the expansion, the E-RMF fits (parameter sets G1 and G2 determined in Ref. [3]) display naturalness and the results are not dominated by the last terms retained [3,4,5,6,9,10,11,12].…”

Density dependence of the symmetry energy from neutron skin thickness in finite nuclei

“…The semi-infinite geometry is free of finite-size effects, Coulomb, and shell effects. Quantal or semiclassical extended Thomas-Fermi (ETF) calculations of asymmetric semi-infinite nuclear matter (ASINM) can be performed to compute Q [39][40][41][42][43][44]. Here we perform ETF calculations of ASINM, since the semiclassical ETF method does not present Friedel oscillations found in the densities of a Hartree-Fock or Hartree calculation of ASINM [45,46].…”

Effect of isospin asymmetry in a nuclear system

“…A surface contribution −α 3 Φ (∇R) 2 /(2g 2 ρ M ) was tested in Ref. [25] and it was found to have absolutely negligible effects. We should note, nevertheless, that very recently it has been shown that couplings of the type Φ 2 R 2 and W 2 R 2 are useful to modify the neutron radius in heavy nuclei while making very small changes to the proton radius and the binding energy [11].…”