Equation of state of neutron star matter and its warm extension with an interacting hadron resonance gas
Yuki Fujimoto (Department of Physics, The University of Tokyo, Tokyo, Japan)
; Kenji Fukushima (Department of Physics, The University of Tokyo, Tokyo, Japan)
; Yoshimasa Hidaka (Institute of Particle and Nuclear Studies, KEK, Tsukuba, Japan, RIKEN iTHEMS, RIKEN, Wako, Japan, Graduate University for Advanced Studies (Sokendai), Tsukuba, Japan); Atsuki Hiraguchi (Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan, Department of Mathematics and Physics, Kochi University, Kochi, Japan)
; Kei Iida (Department of Mathematics and Physics, Kochi University, Kochi, Japan)
We propose an interpolating equation of state that satisfies phenomenologically established boundary conditions in two extreme regimes at high temperature and low baryon density and at low temperature and high baryon density. We confirm that the hadron resonance gas model with the Carnahan-Starling excluded volume effect can reasonably fit the empirical equation of state at high density up to several times the normal nuclear density. We identify the onsets of strange particles and quantify the strangeness contents in dense matter. We finally discuss the finite temperature effects and estimate the thermal index as a function of the baryon density, which should be a crucial input for the core-collapse supernova and the binary neutron star merger simulations.