scholarly journals Symmetry Energy, Neutron Star Crust and Neutron Skin Thickness

2010 ◽  
Vol 50 (1-4) ◽  
pp. 327-329
Author(s):  
Isaac Vidaña ◽  
Constança Providência ◽  
Artur Polls ◽  
Arnau Rios
Universe ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 119 ◽  
Author(s):  
G. Fiorella Burgio ◽  
Isaac Vidaña

Background. We investigate possible correlations between neutron star observables and properties of atomic nuclei. In particular, we explore how the tidal deformability of a 1.4 solar mass neutron star, M1.4, and the neutron-skin thickness of 48Ca and 208Pb are related to the stellar radius and the stiffness of the symmetry energy. Methods. We examine a large set of nuclear equations of state based on phenomenological models (Skyrme, NLWM, DDM) and ab initio theoretical methods (BBG, Dirac–Brueckner, Variational, Quantum Monte Carlo). Results: We find strong correlations between tidal deformability and NS radius, whereas a weaker correlation does exist with the stiffness of the symmetry energy. Regarding the neutron-skin thickness, weak correlations appear both with the stiffness of the symmetry energy, and the radius of a M1.4. Our results show that whereas the considered EoS are compatible with the largest masses observed up to now, only five microscopic models and four Skyrme forces are simultaneously compatible with the present constraints on L and the PREX experimental data on the 208Pb neutron-skin thickness. We find that all the NLWM and DDM models and the majority of the Skyrme forces are excluded by these two experimental constraints, and that the analysis of the data collected by the NICER mission excludes most of the NLWM considered. Conclusion. The tidal deformability of a M1.4 and the neutron-skin thickness of atomic nuclei show some degree of correlation with nuclear and astrophysical observables, which however depends on the ensemble of adopted EoS.


2017 ◽  
Vol 32 (30) ◽  
pp. 1730027 ◽  
Author(s):  
Francesca Sammarruca

After recalling basic phenomenological features of isospin asymmetric nuclear matter, we review predictions for the interaction part of the symmetry energy obtained from different microscopic approaches. The predictions are compared to updated constraints extracted from heavy-ion (HI) reaction observables of a recent GSI experiment. The discussion is extended to the neutron skin thickness in [Formula: see text] and its relation to the density derivative of the symmetry energy. We underline the importance of giving proper consideration to the theoretical uncertainties of microscopic predictions in order to guide phenomenological analyses. In the end, we report briefly on preliminary neutron star calculations based on chiral nuclear forces and outline future plans.


2017 ◽  
Vol 96 (2) ◽  
Author(s):  
Soonchul Choi ◽  
Ying Zhang ◽  
Myung-Ki Cheoun ◽  
Youngshin Kwon ◽  
Kyungsik Kim ◽  
...  

2018 ◽  
Vol 27 (06) ◽  
pp. 1850049 ◽  
Author(s):  
M. Pal ◽  
S. Chakraborty ◽  
B. Sahoo ◽  
S. Sahoo

We analyze the relation between the symmetry energy coefficient [Formula: see text] of finite nuclei with mass number [Formula: see text] in the semi-empirical mass formula. The nuclear matter symmetry energy [Formula: see text] at reference density [Formula: see text] in the subsaturation density region can be determined by the symmetry energy [Formula: see text] and its density slope [Formula: see text] at the saturation density [Formula: see text]. From this relation, the neutron skin thickness ‘[Formula: see text]’ in finite nuclei with droplet model are correlated to the various symmetry energy parameters. A prominent role of the bulk symmetry energy [Formula: see text] to the so-called surface stiffness coefficient [Formula: see text] is observed in deriving the size of the neutron skin. Two types of neutron skins are distinguished: the “surface” and the “bulk”. The linear dependence of the neutron skin thickness for different stable nuclei ([Formula: see text]) on the slope [Formula: see text] of the symmetry energy as well as on the relative neutron excess [Formula: see text] is observed. Though the value of the surface width is found to be limited within 0.1[Formula: see text]fm, its contribution should not be neglected to measure neutron skin thickness.


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