Pseudoconformal behavior color-flavor-locked quark matter within a nonlocal chiral quark model
Oleksii Ivanytskyi (IFT)

Abstract:
I propose a three-flavor nonlocal Nambu–Jona-Lasinio model of quark matter with the scalar attractive, vector repulsive and diquark pairing interaction channels to study the question about possible approximately conformal behavior of the strongly interacting matter existing in the interiors of neutron stars. The model qualitatively agrees with the perturbative quantum chromodynamics (QCD), which predicts asymptotic conformal behavior of quark matter. Particularly, a color superconducting color-flavor-locked (CFL) state is shown to be the ground one at asymptotically high densities. The conformal limit of speed of sound and dimensionless interaction measure are also shown to be reached from below and above, respectively. The model exhibits a narrow range of densities close to central densities of the heaviest neutron stars, where the speed of sound and dimensionless interaction measure simultaneously attain almost conformal values. To test the hypothesis of approximately conformal behavior of quark matter in neutron stars I construct a microscopic quantity, which characterizes single particle excitations of quarks and quantifies deviation from the conformal behavior of quark matter. Analysis of this quantity does not support the assumption about the nearly conformal behavior of quark matter even in the mentioned density range, where its speed of sound and dimensionless interaction measure attain the conformal behavior.