Effective field theory for neutron stars with strong Σ^–‐hyperon repulsion

Abstract

We investigate the role of many-body correlations in the maximum mass of neutron stars using the effective relativistic QHD-model with parameterized couplings which represents an extended compilation of other effective models found in the literature. Our model exhausts the whole fundamental baryon octet (n, p, Σ − , Σ 0 , Σ + , Λ, Ξ − , Ξ 0 ) and simulates corrections to the minimal Yukawa couplings by considering many-body nonlinear self-couplings and meson-meson interaction terms involving scalar-isoscalar (σ, σ * ), vector-isoscalar (ω, φ), vector-isovector ( ) and scalar-isovector (δ). Following recent experimental results, we consider in our calculations the extreme case where the Σ − experiences such a strong repulsion that it does not appear at all in nuclear matter.

A review on the relativistic effective field theory with parameterized couplings for nuclear matter and neutron stars

“…This last result allows, through the calculation of the TOV equations[1], to obtain a maximum mass of neutron stars in good agreement with recent experimental observations[17]. The remaining model parameters, not shown in the curves, are set equal to zero[10]. (b) On the right, for comparison, the curves show the predictions of our model for the equation of state for a particular set of parameters and kaon degrees of freedom.…”

“…[17]). The thin horizontal line corresponds to a canonical 1.44M neutron star with radius 12.5 ± 0.5 km [10]. (b) On the right, similar results taking into account the presence of kaons [11].…”

“…The remaining model parameters, not shown in the curves, are set equal to zero[11]. (a) On the left, population profile as a function of the stellar radius for the particular set of parameters[10]. (b) On the right, similar results taking into account the presence of kaons[11].…”