相关论文: The High-Density Symmetry Energy and Direct Urca
The density dependence of the symmetry energy in relativistic mean-field models with density dependent couplings is discussed in terms of the possible opening of nucleonic direct Urca processes inside neutron stars, which induce a very…
The symmetry energy characterizes the isospin dependent part of the equation of state of isospin asymmetric strong interaction matter and it plays a critical role in many issues of nuclear physics and astrophysics. In this talk, we briefly…
An ambitious goal of the astrophysical community is not only to constrain the equation of state (EOS) of neutron star (NS) matter by confronting it with astrophysics observations, but ultimately also to infer the NS composition.…
We calculate the symmetry energy of the nuclear matter by using the bottom-up approach, so called hard wall model. To consider the nuclear matter, we introduce the isospin for u- and d-quarks. We find that in the hard wall model, the…
The effective chiral model is extended by introducing the contributions from the cross-couplings between isovector and isoscalar mesons. These cross-couplings are found to be instrumental in improving the density content of the nuclear…
The energy of a free gas of neutrons and protons is well known to be approximately isospin parabolic with a negligibly small quartic term of only $0.45$ MeV at the saturation density of nuclear matter $\rho_0=0.16/\rm{fm}^3$. Using an…
The symmetry energy expansion was developed to connect isospin symmetric matter probed in nuclear experiments to asymmetric matter found in neutron stars. Using the isospin asymmetry derived from the Gell-Mann-Nishijima formula, we derive…
Both the symmetry energy part and excluded volume corrections to the equation of state play an important role for the neutron star interior structure and composition, namely for the profile of the baryon density and the proton fraction.…
We investigate the nuclear symmetry energy and neutron star properties using a Bayesian analysis based on constraints from different chiral effective field theory calculations using new energy density functionals that allow for large…
It is shown that behavior of the nuclear symmetry energy is the key quantity in the stability consideration in neutron star matter. The symmetry energy controls the position of crust-core transition and also may lead to new effects in the…
The roles of isospin asymmetry in nuclei and neutron stars are investigated using a range of potential and field-theoretical models of nucleonic matter. The parameters of these models are fixed by fitting the properties of homogeneous bulk…
The cooling of neutron stars by URCA processes in the kaon-condensed neutron star matter for various forms of nuclear symmetry energy is investigated. The kaon-nucleon interactions are described by a chiral lagrangian. Nuclear matter energy…
In confined hadronic matter, the spontaneous breaking and restoration of chiral symmetry can be described by considering nucleons, $N_{+}(939)$, and excited states of opposite parity, $N_{-}(1535)$. In a cold, dense hadronic phase where…
The symmetry energy of nuclear matter is a fundamental ingredient in the investigation of exotic nuclei, heavy-ion collisions and astrophysical phenomena. New data from heavy-ion collisions can be used to extract the free symmetry energy…
We examine the influence of the density dependence of the symmetry energy on several properties of neutron stars. In particular, we study the constraints set on the nuclear matter equation of state by the values of the tidal deformability…
The functional form of the nuclear symmetry energy has only been determined in a very narrow range of densities. Uncertainties concern both the low as well as the high density behaviour of this function. In this work different shapes of the…
If deconfined quark matter exists inside compact stars, the primary cooling mechanism is neutrino radiation via the direct Urca processes d->u+e+antinu_e and u+e->d+nu_e. Below a critical temperature, T_c, quark matter forms a colour…
Asymmetric nuclear matter is treated in the formalism of Dirac-Brueckner approach with Bonn one-boson-exchange nucleon-nucleon interaction. We extract the symmetry energy coefficient at the saturation to be about 31 MeV, which is in good…
In the present study we analyse the effect of the density dependence of the symmetry energy on the hyperonic content of neutron stars within a relativistic mean field description of stellar matter. For the $\Lambda$-hyperon, we consider…
The quantum chromodynamics (QCD) phase diagram at large densities and low temperatures can be probed using both neutron stars and low-energy heavy-ion collisions. Heavy-ion collisions are nearly isospin-symmetric systems, whereas neutron…