Delta baryons and diquark formation in the cores of neutron stars
Delta baryons and diquark formation in the cores of neutron stars
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DOI：
10.1103/physrevd.102.063008
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发表时间：
2020-08
影响因子：
5
通讯作者：
G. Malfatti;M. Orsaria;I. F. Ranea-Sandoval;G. Contrera;F. Weber
中科院分区：
文献类型：
--
作者：
G. Malfatti;M. Orsaria;I. F. Ranea-Sandoval;G. Contrera;F. Weber
我们研究了冷中子星的强子-夸克相变，根据（i）观测到的重夸克的最大质量的限制，（ii）由中子-星星合并中发射的引力波推断的潮汐性质的约束，和（iii）由NICER观测到的中子星星上的热点得到的质量和半径约束。特别注意的是，在中子星星物质中可能存在的$\Delta（1232）$重子。我们的研究结果表明，这种粒子可以构成中子星中重子的很大一部分，因此对这些物体的性质，特别是它们的半径有显着的影响。这部分是由低密度的外观$\Delta$s的介子超子，SU（3）ESC 08模型，介子-$\Delta$耦合常数的理论上可辩护的范围广泛。强子物质的夸克物质的过渡，在2SC+s凝聚相治疗，发现只发生在中子星非常接近的质量峰。然而，夸克物质仍然可能构成恒星总物质的一个可观的部分，如果相变被视为麦克斯韦式（尖锐），在这种情况下，位于引力质量峰值之外的中子星将保持稳定对抗引力坍缩。在这种情况下，对引力坍缩的不稳定性被转移到一个新的（终端）质量，不同于恒星序列的最大质量，产生稳定的紧凑物体，其引力质量与传统分支上的中子星相同，但其半径最多小1公里。我们研究的状态方程的所有模型都在Annala最近建立的范围内。（Nature Physics，2020）
We investigate the hadron-quark phase transition in cold neutron stars in light of (i) the observed limits on the maximum-mass of heavy pulsars, (ii) constraints on the tidal properties inferred from the gravitational waves emitted in binary neutron-star mergers, and (iii) mass and radius constraints derived from the observation of hot spots on neutron star observed with NICER. Special attention is directed to the possible presence of $\Delta(1232)$ baryons in neutron star matter. Our results indicate that this particle could make up a large fraction of the baryons in neutron stars and thus have a significant effect on the properties of such objects, particularly on their radii. This is partially caused by the low density appearance of $\Delta$s for a wide range of theoretically defensible sets of meson-hyperon, SU(3) ESC08 model, and meson-$\Delta$ coupling constants. The transition of hadronic matter to quark matter, treated in the 2SC+s condensation phase, is found to occur only in neutron stars very close to the mass peak. Nevertheless, quark matter may still constitute an appreciable fraction of the stars' total matter if the phase transition is treated as Maxwell-like (sharp), in which case the neutron stars located beyond the gravitational mass peak would remain stable against gravitational collapse. In this case, the instability against gravitational collapse is shifted to a new (terminal) mass different from the maximum-mass of the stellar sequence, giving rise to stable compact objects with the same gravitational masses as those of the neutron stars on the traditional branch, but whose radii are smaller by up to 1 km. All models for the equation of state of our study fall comfortably within the bound established very recently by Annala {\it et al.} (Nature Physics, 2020)