Abstract:
The cores of massive neutron stars can reach densities 5~10 times that of nuclear saturation density, where hadron deconfinement phase transition is highly plausible. In this work, we investigate the structural properties of the hadron-quark mixed phases and their impact on the characteristics of neutron stars. Furthermore, we delve into the possibility of the existence of a pure quark phase core within neutron stars. We investigate the properties of the hadron-quarkpastaphases and their influences on the equation of state (EOS) for neutron stars. In this work, we extend the energy minimization (EM) method to describe the hadron-quarkpastaphase, where the surface and Coulomb contributions are included in the minimization procedure. By allowing different electron densities in the hadronic and quark matter phases, the total electron chemical potential with the electric potential remains constant, and local
β equilibrium is achieved inside the Wigner-Seitz cell. We employ the relativistic mean-field model to describe the hadronic matter, while the quark matter is described by the MIT bag model with vector interactions. It is found that the vector interactions among quarks can significantly stiffen the EOS at high densities and help enhance the maximum mass of neutron stars. Other parameters like the bag constant can also affect the deconfinement phase transition in neutron stars. Our results show that hadron-quarkpastaphases may appear in the core of massive neutron stars that can be compatible with current observational constraints.