808 research outputs found
Hypermatter in chiral field theory
We investigate the properties of hadronic matter and nuclei be means of a
generalized model with broken scale invariance. In
mean-field approximation, vector and scalar interactions yield a saturating
nuclear equation of state. Finite nuclei can be reasonably described, too. The
condensates and the effective baryon masses at finite baryon density and
temperature are discussed.Comment: uses IOP style, to be published in Journal of Physics, Proceedings of
the International Symposium on Strangeness in Quark Matter 1997, April 14-18,
Thera (Santorini), Hella
Chiral model for dense, hot and strange hadronic matter
An extended chiral SU(3) model is applied to the description of dense, hot
and strange hadronic matter. The degrees of freedom are the baryon octet and
decuplet and the spin-0 and spin-1 meson multiplets. The parameters of the
model are fitted to the hadron masses in vacumm, infinite nuclear matter
properties and soft pion theorems. At high densities the appearance of density
isomers cannot be ruled out and extrapolation to finite temperature exhibits a
first order phase transition at . The predicted dropping
baryon masses lead to drastically changed particle ratios compared to ideal gas
calculations.Comment: 4 pages, 3 figures, Contribution to the Proceedings of the 15th
Particles and Nuclei International Conference (PANIC 99), Uppsala, Sweden,
June 10-16, 199
Nuclear and Neutron Star Radii
We investigate the correlation between nuclear neutron radii and the radius
of neutron stars. We use a well-established hadronic SU(3) model based on
chiral symmetry that naturally includes non-linear vector meson and scalar
meson - vector meson couplings. The relative strengths of the couplings modify
the nuclear isospin-dependent interactions. We study the dependence of nuclear
and neutron star radii on the coupling strengths. The relevance of the results
for parity-violating electron-nucleus scattering and the URCA process in
neutron stars is discussed
Chiral Symmetry Restoration and Deconfinement to Quark Matter in Neutron Stars
We describe an extension of the hadronic SU(3) non-linear sigma model to
include quarks. As a result, we obtain an effective model which interpolates
between hadronic and quark degrees of freedom. The new parameters and the
potential for the Polyakov loop (used as the order parameter for deconfinement)
are calibrated in order to fit lattice QCD data and reproduce the QCD phase
diagram. Finally, the equation of state provided by the model, combined with
gravity through the inclusion of general relativity, is used to make
predictions for neutron stars.Comment: Prepared for Light-Cone 2009, Sao Jose dos Campos, Brazil, 8-13 July
2009
Neutron star properties in a chiral SU(3) model
We investigate various properties of neutron star matter within an effective
chiral model. The predictions of this model are
compared with a Walecka-type model. It is demonstrated that the importance of
hyperon degrees are strongly depending on the interaction used, even if the
equation of state near saturation density is nearly the same in both models.
While the Walecka-type model predicts a strange star core with strangeness
fraction , the chiral model allows only for
and predicts that , and will not exist in star, in
contrast to the Walecka-type model.Comment: 13 pages, Revtex, 5 figs include
- …