AI 中文总结
研究差速旋转能否提高含超子EoS构建的中子星最大质量，采用CST方法和RMF模型，发现差速旋转可增加最大质量，能符合GW 190814推断的质量范围，但软EoS即便有差速旋转也不满足PSR~J0740+6620的约束，还分析了内部结构等。
AI 中文摘要
中子星的最大质量为致密物质的状态方程（EoS）提供了关键约束。近期观测对一大类软EoS施加了强约束，而GW 190814中质量为2.50 - 2.67 $M_{\odot}$的致密天体的可能存在进一步挑战了我们对致密物质的理解。此外，包含超子自由度通常会软化EoS。本文采用Cook-Shapiro-Teukolsky（CST）方法构建差速旋转中子星的平衡构型，采用含超子自由度的相对论平均场（RMF）模型。结果表明差速旋转可大幅增加最大质量，但足够软的EoS即使应用差速旋转也无法满足PSR~J0740+6620的约束。还对平衡构型的内部结构进行了系统分析，证明了准环形构型的存在并给出了极端差速旋转下包含完整重子八重态的平衡序列。
英文摘要
The maximum mass of neutron stars provides a key constraint on the equation of state (EoS) of dense matter. Recent observations, including the ${\approx}2 M_{\odot}$ pulsar PSR~J0740+6620, have placed strong constraints on a large class of soft EoSs, while the possible existence of a compact object with a mass of $2.50$ - $2.67$ $M_{\odot}$ in GW 190814 further challenges our understanding of dense matter. Moreover, the inclusion of hyperonic degrees of freedom generally softens the EoS, making it difficult to support massive neutron stars even when the $2$ $M_{\odot}$ constraint is satisfied (a problem known as the hyperon puzzle). In this work, we investigate whether differential rotation can enhance the maximum mass of neutron stars constructed with an EoS including hyperons, thereby addressing the maximum-mass constraints imposed by current observations. We employ the Cook-Shapiro-Teukolsky (CST) approach, a numerically improved reformulation of the Komatsu-Eriguchi-Hachisu (KEH) scheme, to construct equilibrium configurations of differentially rotating neutron stars. For the nuclear matter EoS, we adopt a relativistic mean-field (RMF) model incorporating hyperonic degrees of freedom through an SU(6) symmetric coupling scheme. We find that differential rotation can substantially increase the maximum mass, yielding configurations consistent with the mass range inferred from GW 190814. However, a sufficiently soft EoS fails to satisfy the constraint from PSR~J0740+6620 (346 Hz) even with differential rotation applied. We also present a systematic analysis of the internal structure of the resulting equilibrium configurations. Furthermore, we demonstrate the existence of quasi-toroidal configurations and present equilibrium sequences incorporating the full baryon octet under extreme differential rotation.
Comments17 pages, 11 figures, 4 tables, Submitted to Physical Review D
