The Σ Well Depth and the Proto Neutron Star Matter

Abstract

The effect of the Σ well depth \(U_{\varSigma}^{(N)}\) on a proto neutron star (PNS) is examined within the framework of relativistic mean field theory for the baryon octet system. It is found that the well depth \(U_{\varSigma}^{(N)}\) will affect the structures of the PNS. With the well depth \(U_{\varSigma}^{(N)}\) growing from 0 to 30 MeV, the field strength of meson ρ, the chemical potentials of electrons and neutrons, the relative number density of p, e, μ, Λ, Ξ0, the mass and the pressure of a PNS all increase while the relative number density of n, Ξ−, Σ−, Σ0, Σ+ decrease. It is also found that the larger changes of the hyperon coupling constants, which is connected to the Σ well depth \(U_{\varSigma}^{(N)}\), will lead to the smaller changes in the neutron star mass and this shows the mass of PNS is not very sensitive to the hyperon coupling constants.