EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

2006 ◽  
Vol 23 (5) ◽  
pp. 1139-1141 ◽  
Author(s):  
Geng Li-Sheng ◽  
Meng Jie ◽  
Toki Hiroshi ◽  
Long Wen-Hui ◽  
Shen Gang

2020 ◽  
Vol 638 ◽  
pp. A40
Author(s):  
A. Mantziris ◽  
A. Pastore ◽  
I. Vidaña ◽  
D. P. Watts ◽  
M. Bashkanov ◽  
...  

We present the extension of a previous study where, assuming a simple free bosonic gas supplemented with a relativistic mean-field model to describe the pure nucleonic part of the equation of state, we studied the consequences that the first non-trivial hexaquark d*(2380) could have on the properties of neutron stars. Compared to that exploratory work, we employ a standard non-linear Walecka model including additional terms that describe the interaction of the d*(2380) di-baryon with the other particles of the system through the exchange of σ- and ω-meson fields. Our results show that the presence of the d*(2380) leads to maximum masses compatible with recent observations of ∼2 M⊙ millisecond pulsars if the interaction of the d*(2380) is slightly repulsive or the d*(2380) does not interact at all. An attractive interaction makes the equation of state too soft to be able to support a 2 M⊙ neutron star whereas an extremely repulsive one induces the collapse of the neutron star into a black hole as soon as the d*(2380) appears.


Author(s):  
Jinniu Hu ◽  
Shishao Bao ◽  
Ying Zhang ◽  
Ken’ichiro Nakazato ◽  
Kohsuke Sumiyoshi ◽  
...  

Abstract The radii and tidal deformabilities of neutron stars are investigated in the framework of the relativistic mean-field (RMF) model with different density-dependent behaviors of symmetry energy. To study the effects of symmetry energy on the properties of neutron stars, $\omega$ meson and $\rho$ meson coupling terms are included in a popular RMF Lagrangian, i.e., the TM1 parameter set, which is adopted for the widely used supernova equation of state (EoS) table. The coupling constants relevant to the vector–isovector meson, $\rho$, are refitted by a fixed symmetry energy at subsaturation density and its slope at saturation density, while other coupling constants remain the same as the original ones in TM1 so as to update the supernova EoS table. The radius and mass of maximum neutron stars are not so sensitive to the symmetry energy in these family TM1 parameterizations. However, the radii in the intermediate-mass region are strongly correlated with the slope of symmetry energy. Furthermore, the dimensionless tidal deformabilities of neutron stars are also calculated within the associated Love number, which is related to the quadrupole deformation of the star in a static external tidal field and can be extracted from the observation of a gravitational wave generated by a binary star merger. We find that its value at $1.4 \mathrm{M}_\odot$ has a linear correlation to the slope of symmetry energy, unlike that previously studied. With the latest constraints of tidal deformabilities from the GW170817 event, the slope of symmetry energy at nuclear saturation density should be smaller than $60$ MeV in the family TM1 parameterizations. This fact supports the usage of a lower symmetry energy slope for the updated supernova EoS, which is applicable to simulations of neutron star mergers. Furthermore, an analogous analysis is also done within the family IUFSU parameter sets. It is found that the correlations between the symmetry energy slope with the radius and tidal deformability at $1.4 \mathrm{M}_\odot$ have very similar linear relations in these RMF models.


2006 ◽  
Vol 73 (3) ◽  
Author(s):  
Yoko Ogawa ◽  
Hiroshi Toki ◽  
Setsuo Tamenaga ◽  
Satoru Sugimoto ◽  
Kiyomi Ikeda

Sign in / Sign up

Export Citation Format

Share Document