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arXiv · 2301.12690

High-Density behavior of symmetry energy and speed of sound in the dense matter within an effective chiral model

Prashant Thakur·N. K. Patra·T. K. Jha·Tuhin Malik
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Abstract

With an effective chiral model, we investigate how the mesonic cross couplings $\sigma-\rho$ and $\omega-\rho$ affect the density content of the symmetry energy and its higher-order slope parameters. Earlier mentioned cross-couplings are crucial to controlling the density content of symmetry energy. For this purpose, we did a case study for different values of the symmetry energy $J_1$, defined at density 0.1 fm$^{-3}$ in the range (23.4 - 25.2) for a fixed value of the slope of the symmetry energy $L_0 = 60$ MeV at saturation density and investigate its effect on the higher-order coefficients and their influence on the underlying equation of state. We found that the model with $J_1= 24.6$ MeV is more favorable with the pure neutron matter (PNM) constraints obtained from $\chi$EFT calculations. In addition, we show that all of our models predict a monotonically increasing speed of sound up to four times the saturation density. The speed of sound decreases/saturates above that point and approaches the conformal limit approximately $\sqrt{1/3}~c$ at the center of the maximum mass star.

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Prashant Thakur, N. K. Patra, T. K. Jha, Tuhin Malik. 2023-01-30. High-Density behavior of symmetry energy and speed of sound in the dense matter within an effective chiral model. https://arxiv.org/abs/2301.12690

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