Equation of State for Hyperonic Neutron-Star Matter in SU(3) Flavor Symmetry

Using a relativistic mean-field model calibrated to finite-nucleus observables and bulk properties of dense nuclear matter, we investigate hyperonic neutron-star matter within an SU(3) flavor symmetry scheme. To retain SU(6)-based couplings within SU(3) flavor symmetry, we introduce a quartic ϕ self-interaction and ϕ-ρ mixing. We demonstrate the roles of αv (F/(F+D) ratio), θv (mixing angle), and zv (singlet-to-octet coupling ratio) in SU(3)-invariant vector-meson couplings. It is found that zv predominantly controls the maximum mass of a neutron star, and 2M⊙ neutron stars can be supported for zv≤0.15. The αv also helps sustain large masses, whereas θv has a smaller effect on neutron-star properties. This SU(3) framework reconciles nuclear and astrophysical constraints and offers a plausible resolution of the hyperon puzzle.