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arXiv 1508.04861nucl-thastro-ph.HEhep-ph
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超子之谜、强子-夸克交叉与大质量中子星

Hyperon Puzzle, Hadron-Quark Crossover and Massive Neutron Stars

Kota Masuda, Tetsuo Hatsuda, Tatsuyuki Takatsuka

摘要:

基于强子-夸克交叉图研究了冷、热中子星的体性质.通过使用一个唯象状态方程(EOS)“CRover”,在约3倍核物质密度处对两相进行插值,发现引力质量大于2太阳质量的冷NS是可以维持的。这与一阶强子-夸克跃迁的情况形成鲜明对比。冷NS的半径与CR在EOS是在一个狭窄的范围内,这是不敏感的NS质量。由于强子-夸克交换导致物态方程硬化,NS核的中心密度最多为核物质密度的4倍,在NS核内部几乎不发生超子混合。这构成了长期存在的超子之谜的解决方案。还用强子-夸克交叉考察了色超导性(CSC)对NS结构的影响。对于双夸克吸引力的典型强度,由于双味CSC(2SC),EOS发生轻微软化,最大质量减少约0.2太阳质量。将CRover物态方程推广到有限温度的超新星物质,描述了诞生时的热超新星。在等熵条件下,强子-夸克交换降低了热NS的中心温度。本文还估算了从热NS到冷NS收缩过程中的引力能释放和自旋加速率。

英文摘要:

Bulk properties of cold and hot neutron stars (NSs) are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density. By using a phenomenological equation of state (EOS) "CRover" which interpolates the two phases at around 3 times the nuclear matter density, it is found that the cold NSs with the gravitational mass larger than 2-solarmass can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition. The radii of the cold NSs with the CRover EOS are in the narrow range which is insensitive to the NS masses. Due to the stiffening of the EOS induced by the hadron-quark crossover, the central density of the NSs is at most 4 times the nuclear matter density and the hyperon-mixing barely occurs inside the NS core. This constitutes a solution of the long-standing hyperon puzzle. The effect of color superconductivity (CSC) on the NS structures is also examined with the hadron-quark crossover. For the typical strength of the diquark attraction, a slight softening of the EOS due to two-flavor CSC (2SC) takes place and the maximum mass is reduced by about 0.2-solarmass. The CRover EOS is generalized to the supernova matter at finite temperature to describe the hot NSs at birth. The hadron-quark crossover is found to decrease the central temperature of the hot NSs under isentropic condition. The gravitational energy release and the spin-up rate during the contraction from the hot NS to the cold NS are also estimated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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