33 research outputs found
Model of the Phase Transition Mimicking the Pasta Phase in Cold and Dense Quark-Hadron Matter
A simple mixed phase model mimicking so-called "pasta" phases in the
quark-hadron phase transition is developed and applied to static neutron stars
for the case of DD2 type hadonic and NJL type quark matter models. The
influence of the mixed phase on the mass-radius relation of the compact stars
is investigated. Model parameters are chosen such that the results are in
agreement with the observational constraints for masses and radii of pulsars.Comment: 6 pages, 4 figure
Chirally improved quark Pauli blocking in nuclear matter and applications to quark deconfinement in neutron stars
The relativistic mean field (RMF) model of the nuclear matter equation of
state has been modified by including the effect of Pauli-blocking owing to
quark exchange between the baryons. Different schemes of a chiral enhancement
of the quark Pauli blocking have been suggested according to the adopted
density dependence of the dynamical quark mass. The resulting equations of
state for the pressure are compared to the RMF model DD2 with excluded volume
correction. On the basis of this comparison a density-dependent nucleon volume
is extracted which parametrises the quark Pauli blocking effect in the
respective scheme of chiral enhancement. The dependence on the isospin
asymmetry is investigated and the corresponding density dependent nuclear
symmetry energy is obtained in fair accordance with phenomenological
constraints. The deconfinement phase transition is obtained by a Maxwell
construction with a quark matter phase described within a higher order NJL
model. Solutions for rotating and nonrotating (hybrid) compact star sequences
are obtained which show the effect of high-mass twin compact star solutions for
the rotating case.Comment: 20 pages, 12 figures, 3 tables, text revised and extended, figures
updated, references added, accepted for publication in Particles (2020