Optimization of relativistic mean field model for finite nuclei to neutron star matter

Abstract

We have optimized the parameters of extended relativistic mean-field model using a selected set of global observables which includes binding energies and charge radii for nuclei along several isotopic and isotonic chains and the iso-scalar giant monopole resonance energies for the 90 Zr and 208 Pb nuclei. The model parameters are further constrained by the available informations on the energy per neutron for the dilute neutron matter and bounds on the equations of state of the symmetric and asymmetric nuclear matter at supra-nuclear densities. Two new parameter sets BSP and IUFSU* are obtained, later one being the variant of recently proposed IUFSU parameter set. The BSP parametrization uses the contributions from the quartic order cross-coupling between ω and σ mesons to model the high density behaviour of the equation of state instead of the ω meson selfcoupling as in the case of IUFSU* or IUFSU. Our parameter sets yield appreciable improvements in the binding energy systematics and the equation of state for the dilute neutron matter. The importance of the quartic order ω − σ cross coupling term of the extended RMF model, as often ignored, is realized.

Anisotropic pressure and hyperons in neutron stars

“…For examples IUFSU parameter set 20 yields M max = 1.94 M ⊙ and BSP parameter set 21 yields M max = 2.02 M ⊙ . On the other hand, the presence of only nucleons and leptons in NS core is physically not too realistic.…”

Critical density and impact ofΔ(1232)resonance formation in neutron stars

“…Given the density dependencies of the symmetry energy and self-energies, this equation determines the ρ The nonlinear RMF model has been very successful in describing many nuclear properties and phenomena during the last few decades, see e.g., refs. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59]. The total Lagrangian density of the nonlinear RMF model of ref.…”

Cracking on anisotropic neutron stars

“…We need to note that the BSP parameter set produced acceptable predictions of finite nuclei and nuclear matter properties. Furthermore, in intermediate density region, its EOS predictions are quite compatible to the ones extracted from heavy ions data [14]. On the other hand, the SU(6) symmetry and potential depths are used because the experimental data of hyper-nuclei properties are limited.…”

“…To obtain the realistic NS core EOS, BSP parameter set for nucleon coupling constants and the parameters of nonlinear meson terms [14] are used. While to determine the hyperon coupling constants, SU(6) symmetry parameters and the hyperon potential depth experimental values are used [15].…”

“…Therefore, in this work, we will focus our investigation on this matter. Similar to the one done in Reference [8], in this work to describe NS core EOS, we use extended version of relativistic mean field (ERMF) model where in nucleon sector BSP parameters set of Reference [14] is used and in hyperon sector the potential depth and SU(6) symmetry are used to determined the corresponding parameters [15]. While for the crust EOS, we use the one calculated by Miyatsu et al [1].…”