Narrow Results

The ground state energies, sizes and deformations of 1897 even–even nuclei with 10≤Z ≤110 have been carried out by using the Relativistic Mean Field (RMF) model. In the present calculations, the nonlinear RMF force NL3* recent refitted version of the NL3 force has been used. The BCS (Bardeen–Cooper–Schrieffer) formalism with constant gap approximation has been taken into account for pairing correlations. The predictions of RMF model for the ground state properties of some nuclei have been discussed in detail.

The effects of auxiliary contribution in forms of electromagnetic tensors and relativistic electromagnetic exchange in local density approximation as well as δ meson and isovector density-dependent nonlinear terms in standard relativistic mean field model constrained by nuclear matter stability criteria in some selected finite nuclei and nuclear matter properties are studied. It is found that in the case of finite nuclei, the electromagnetic tensors play the most dominant part compared to other auxiliary terms. Due to the presence of electromagnetic tensors, the binding energies prediction of the model can be improved quite significantly. However, these terms do not yield demanded effects for rms radii prediction. In the case of nuclear matter properties, the isovector density-dependent nonlinear term plays the most crucial role in providing predictions which are quite compatible with experimental constraints. We have also shown these auxiliary contributions are indeed unable to improve the single particle spectrum results of the model.

An extended nuclear mass formula has been used by considering the bulk, surface and coulomb contributions to the nuclear mass. In this mass formula, the fourth-order symmetry energy coefficient $a_{\mathrm{\text{sym}},4}(A)$ of finite nuclei and fourth-order symmetry energy $E_{\mathrm{\text{sym}},4}({\rho }_0)$ of nuclear matter (NM) are related explicitly to the characteristic parameters of NM equation of state (EOS) using finite range effective interaction. The calculations are carried out with Yukawa form of exchange interaction having the same range but with different strengths for interaction between like and unlike nucleon. In this extended mass formula, by approximating $a_{\mathrm{\text{sym}},4}(A)$ to a constant $c_{\mathrm{\text{sym}},4}$ an explicit relation between $a_{\mathrm{\text{sym}},4}(A)$ and fourth-order symmetry energy $E_{\mathrm{\text{sym}},4}({\rho }_0)$ is obtained, which provides the possibility to extract information on $E_{\mathrm{\text{sym}},4}({\rho }_0)$.

The secondary component of the GW190814 event left us with a question, “whether it is a supermassive neutron star or lightest black-hole?” Recently, Fattoyev et al. obtained an energy density functional (EDF) named as BigApple, which reproduces the mass of the neutron star is 2.60 $M_{\odot }$ which is well consistent with GW190814 data. This study explores the properties of finite nuclei, nuclear matter and neutron stars by using the BigApple EDF along with four well-known relativistic mean-field forces, namely NL3, G3, IOPB-I and FSUGarnet. The finite nuclei properties like binding energy per particle, skin thickness, charge radius, single-particle energy, and two-neutron separation energy are well predicted by the BigApple for a series of nuclei. The calculated nuclear matter quantities, such as incompressibility, symmetry energy and slope parameters at saturation density, are consistent with the empirical or experimental values where ever available. The predicted canonical tidal deformability by the BigApple parameter set is well-matched with the GW190814 data. Also, the dimensionless moment of inertia lies in the range given by the analysis of PSR J0737-3039A.

Exploring the isospin dependence of the nuclear matter is one of the main challenges of modern nuclear physics. The ab initio calculations are the proper tool for these investigations. Results of the Dirac-Brueckner-Hartree-Fock calculations for asymmetric nuclear matter, which are based on improved approximation schemes, are presented. Furthermore, the application to finite nuclei is discussed.