Critical density and impact of Δ(1232) resonance formation in neutron stars
Critical density and impact of Δ(1232) resonance formation in neutron stars
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DOI：
10.1103/physrevc.92.015802
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发表时间：
2015-01
影响因子：
3.1
通讯作者：
Bao-Jun Cai;F. J. Fattoyev;Bao-An Li;W. Newton
中科院分区：
文献类型：
--
作者：
Bao-Jun Cai;F. J. Fattoyev;Bao-An Li;W. Newton
在扩展的非线性相对论平均场模型下研究了中子星中形成\D共振的临界密度和影响。发现形成四种不同电荷态的\D的临界密度不同地依赖于核对称能的单独的动能和势能部分，这是中子星微物理性质的第一个例子。此外，它们对介质中的δ质量m_{\Delta}$和完全未知的δ-$\rho$耦合强度g_{\rho\Delta}$都很敏感。在普遍的重子-介子耦合方案中，假设各自的$\Delta$-介子和核子-介子耦合常数相同，发现第一个$\Delta^-（1232）$出现的临界密度为\rc=$（2.08\pm0.02）\rho_0$使用与通常用于表征状态方程的所有七个宏观参数的当前约束一致的RMF模型参数（EoS）的同位旋不对称核物质（ANM）在饱和密度$\rho_0$。此外，我们还发现中子星的组成和质量-半径关系与g_{\rho\Delta}$和m_{\Delta}$的值密切相关。
The critical densities and impact of forming \D resonances in neutron stars are investigated within an extended nonlinear relativistic mean-field (RMF) model. The critical densities for the formation of four different charge states of \D are found to depend differently on the separate kinetic and potential parts of nuclear symmetry energy, the first example of a microphysical property of neutron stars to do so. Moreover, they are sensitive to the in-medium Delta mass $m_{\Delta}$ and the completely unknown $\Delta$-$\rho$ coupling strength $g_{\rho\Delta}$. In the universal baryon-meson coupling scheme where the respective $\Delta$-meson and nucleon-meson coupling constants are assumed to be the same, the critical density for the first $\Delta^-(1232)$ to appear is found to be \rc=$(2.08\pm0.02)\rho_0$ using RMF model parameters consistent with current constraints on all seven macroscopic parameters usually used to characterize the equation of state (EoS) of isospin-asymmetric nuclear matter (ANM) at saturation density $\rho_0$. Moreover, the composition and the mass-radius relation of neutron stars are found to depend significantly on the values of the $g_{\rho\Delta}$ and $m_{\Delta}$.