The existence of light QCD axions, whose mass depends on an additional free parameter, can lead to a new ground state of matter, where the sourced axion field reduces the nucleon effective mass. The presence of the axion field has structural consequences, in particular, it results in a thinner (or even prevents its existence) heat-blanketing envelope, significantly altering the cooling patterns of neutron stars. We exploit the anomalous cooling behavior to constrain previously uncharted regions of the axion parameter space by comparing model predictions with existing data from isolated neutron stars. Notably, this analysis does not require the light QCD axion to be the dark matter candidate. Published by the American Physical Society 2024

中文翻译：

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用孤立的中子星冷却约束轻 QCD 轴子


轻 QCD 轴子的存在，其质量取决于额外的自由参数，可以导致物质的新基态，其中来源轴子场会降低核子有效质量。轴子场的存在具有结构后果，特别是，它导致热毯包络更薄（甚至阻止其存在），从而显着改变中子星的冷却模式。我们通过将模型预测与孤立中子星的现有数据进行比较，利用异常冷却行为来限制轴子参数空间以前未知的区域。值得注意的是，这种分析不需要光 QCD 轴子成为暗物质候选者。 美国物理学会 2024 年出版