Compact Star Properties from an Extended Linear Sigma Model

Abstract

The equation of state provided by effective models of strongly interacting matter should comply with the restrictions imposed by current astrophysical observations of compact stars. Using the equation of state given by the (axial-)vector meson extended linear sigma model, we determine the mass-radius relation and study whether these restrictions are satisfied under the assumption that most of the star is filled with quark matter. We also compare the mass-radius sequence with those given by the equations of state of somewhat simpler models.

Hybrid star construction with the extended linear sigma model: preliminary results

“…We see that current astrophysical constraints can be sat-isfied in many ways and further, more precise radius measurements would be required to narrow down these possibilities. It is worth to note that the quark-vector meson coupling has a significant effect on the stiffness of the equation of state, although even pure quark stars are not completely excluded currently [10].…”

“…The model contains three flavours of constituent quarks, with kinetic terms and Yukawa-type interactions with the (pseudo)scalar mesons. In addition to the model described in [8], a Yukawa term is also included between the quark and vector meson sector, and a condensate for ω 0 is also introduced, as in [10].…”

Neutron star properties in the (axial)vector meson extended linear sigma model

“…For the quark part, we utilize the (axial)vector meson extended linear sigma model (eLSM), developed and thoroughly investigated in several previous papers (Kovács et al 2016a; Kovács et al 2021; Parganlija et al 2013; Takátsy et al 2019). This is a three‐flavor quark–meson model containing constituent quarks and the complete nonets of (pseudo)scalar and (axial)vector mesons.…”

Térelméleti módszerek az asztrofizikában

“…A σ-ω modellben az M -R görbe alakját és a maximális neutroncsillag tömeget a nukleonok maganyagon belüli, eektív tömege nagy mértékben befolyásolja. Más modellekre vonatkozó vizsgálatokban is hasonló viselkedés tapasztalható, így feltételezhet®, hogy ez nem csak a σ-ω modell jellemz®je, hanem általánosabb jelenség [90,91]. A σ-ω modellre vonatkozó vizsgálatomban végigkövethet®, hogy a paraméterek viselkedése hogyan vezet a fentebb említett következtetésekre, és így utat mutathat a álarc probléma kezeléshez a vizsgálatok és a modellalkotás során.…”