Equation of State of Hypermatter in beta Equilibrium in a Quark Model with Excluded Volume Correction

Abstract

We study the effects of the finite size of the baryons on the equation of state of homogeneous hadronic matter with hyperons. The finite extension of hadrons is introduced in order to improve the perfomance of field theoretical models at very high densities, simulating the short-range hard-core repulsive part of the baryon-baryon potential. We choose the Quark Meson Coupling model to describe the baryon dynamics because this model provides a density dependent radius of the bag. In addition we calculate finite size corrections for the Zimanyi-Moszkowski model in order to make a definite comparison. In both cases finite size effects are implemented through a Van der Waals like correction in the normalization of the baryon fields. In this approach we investigate $β$-stable matter in conditions that could be found in the interior of massive stars. We find that the excluded volume corrections contribute significantly for densities above twice the symmetric nuclear matter saturation density, although for the quark model the results strongly depends upon the equilibrium conditions for the confinement volume immersed in a dense medium.