Multilayer neutron stars with scalar mesons crossing term

The standard relativistic mean field model, extended with σ -δ meson interaction, is applied to study neutron star (NS) properties. In the equation of state including such interaction, the phase transition occurs in the core region of NSs. The phase transition leads to multilayer neutron star structure and to the softening of the equation of state (EOS) in a moderate range of densities. Such an EOS, consequently, makes the neutron star more compact without reducing its maximum mass. The star properties obtained are in very good agreement with the most recent observational data from the LIGO/Virgo gravitational wave detectors and x-ray observations of NICER.