夸克子交叉框架下的有限温度轴子混合中子星
Finite-Temperature Axion-Admixed Neutron Stars in a Quarkyonic Crossover Framework
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中文总结 AI 辅助
本研究在夸克子交叉框架下，考虑有限温度下轴子对中子星质量、半径和形变性的影响，发现轴子主要产生于内部5-11 km区域，且约60%轴子质量集中于中心，对观测性质有显著影响。
中文摘要 AI 辅助
我们分析了轴子贡献对有限温度下中子星（NS）的质量、半径和无量纲形变性的影响。尽管中子星的冷却主要归因于中微子的发射，但也不能排除由于轴子发射而导致的额外冷却。轴子的存在对于解决标准模型内的强CP问题是必要的。Peccei-Quinn（PQ）对称性破缺机制产生了轴子。它们是伪南布-戈德斯通玻色子。它们的质量极小但不为零。这自然解决了强CP破坏参数${\theta} \lesssim 10^{-10}$的微调问题。我们提出，有限温度中子星的特征是夸克核心被重子介质包围，并与轴子混合，轴子是伪标量戈德斯通玻色子，被认为是暗物质（DM）的强候选者。与原始夸克子模型不同，我们在有限温度下构建了一个夸克子启发的平滑交叉状态方程（EoS）。这种平滑交叉避免了尖锐一阶构造中发现的热力学不稳定性。我们将轴子EoS添加到有限温度夸克子EoS中，并求解Tolman-Oppenheimer-Volkoff方程，以估计在不同温度下考虑和不考虑轴子时中子星的性质。我们发现，轴子的产生在恒星内部半径$5-11$ km范围内最大；然而，对质量的影响是显著的，即约$60\\%$的轴子质量集中在恒星的中心区域。我们还发现，与半径不同，温度对中子星质量的影响是微小的。总的来说，轴子对中子星的观测性质有显著影响。这些结果突显了轴子物理学在中子星现象学中的关键作用。
英文摘要
We analyze the effect of axion contribution on the mass, radius and dimensionless deformability of a neutron star (NS) at finite temperature. Although the cooling of an NS is mainly due to the emission of neutrinos, additional cooling cannot be ruled out due to the emission of axions. The existence of an axion is needed for addressing the strong CP problem within the standard model. The Peccei-Quinn (PQ) symmetry breaking mechanism generates axions. They are pseudo-Nambu-Goldstone bosons. Their mass is extremely small but non-zero. This naturally resolves the fine-tuning problem of the strong CP-violating parameter $θ \lesssim 10^{-10}$. We propose that a finite temperature NS feature a quark core surrounded by a baryonic medium admixed with the axions, which are pseudo scalar Goldstone bosons and are considered as strong candidates for the dark matter (DM). Unlike the original quarkyonic model, we formulate a quarkyonic-inspired smooth crossover equation of state (EoS) at finite temperatures. This smooth crossover avoids thermodynamic instabilities found in sharp first-order constructions. We add the axionic EoS to the finite temperature quarkyonic one and solve the Tolman-Oppenheimer-Volkoff equations to estimate the properties of the NS both with and without taking the axion into account at different temperatures. We find that the production of axions is maximum within a radius of $5-11$ km in the star's interior; however, the impact on the mass is significant, i.e., $\sim 60\%$ of axion mass concentrated in the central region of the star. We also find that the effect of temperature on the mass of NS is marginal unlike the radius. In general, the influence of axions is significant for the observational properties of NS. These results highlight the pivotal role of axion physics in neutron star phenomenology.
发表机构
- Institute of Physics, Sachivalaya Marg, Bhubaneswar-751005, India（印度布巴内斯瓦尔物理研究所）
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India（印度孟买霍米巴巴哈国立研究所）
- Department of Physics, Indira Gandhi Institute of Technology, Sarang, Dhenkanal, Odisha-759146, India（印度奥迪沙邦德赫卡纳尔萨拉格英迪拉甘地理工学院物理系）
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