Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Third family of compact stars within a nonlocal chiral quark model
  equation of state   A class of hybrid compact star equations of state is investigated that joins
by a Maxwell construction a low-density phase of hadronic matter, modeled by a
relativistic meanfield approach with excluded nucleon volume, with a
high-density phase of color superconducting two-flavor quark matter, described
within a nonlocal covariant chiral quark model. We find the conditions on the
vector meson coupling in the quark model under which a stable branch of hybrid
compact stars occurs in the cases with and without diquark condensation. We
show that these hybrid stars do not form a third family disconnected from the
second family of ordinary neutron stars unless additional (de)confining effects
are introduced with a density-dependent bag pressure. A suitably chosen density
dependence of the vector meson coupling assures that at the same time the
$2~$M$_\odot$ maximum mass constraint is fulfilled on the hybrid star branch. A
twofold interpolation method is realized which implements both, the density
dependence of a confining bag pressure at the onset of the hadron-to-quark
matter transition as well as the stiffening of quark matter at higher densities
by a density-dependent vector meson coupling. For three parametrizations of
this class of hybrid equation of state the properties of corresponding compact
star sequences are presented, including mass twins of neutron and hybrid stars
at 2.00, 1.39 and 1.20 $M_\odot$, respectively. The sensitivity of the hybrid
equation of state and the corresponding compact star sequences to variations of
the interpolation parameters at the 10% level is investigated and it is found
that the feature of third family solutions for compact stars is robust against
such a variation. This advanced description of hybrid star matter allows to
interpret GW170817 as a merger not only of two neutron stars but also of a
neutron star with a hybrid star or of two hybrid stars.

5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph