Neutrino emission in cold neutron stars is dominated by the modified urca (murca) process and nucleon-nucleon bremsstrahlung. The standard emission rates were provided by Friman and Maxwell in 1979, effectively based on a chiral Lagrangian framework with pion and rho meson exchange, supplemented by Landau parameters to describe short-range interactions. We reevaluate these rates within the same framework, correcting several errors and removing unnecessary simplifications, notably the triangular approximation — where the Fermi momenta of protons and leptons negligible compared to that of neutrons — in MURCA, and quantify their importance. The impact of rho meson exchange, previously argued to cancel with interference effects, is actually quite relevant. Altogether, the cooling rates are reduced by as much as a factor 2. We provide comprehensive analytical formulas encompassing all contributions, designed for straightforward numerical implementation. Our results are particularly relevant for studies of physics beyond the standard model, where the emission of new particles — such as axions — is typically computed within the same framework we adopt here.

中文翻译：

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冷中子星中的中微子发射：重新审视轫致辐射率和修正的 urca 速率


冷中子星中的中微子发射以改进的 urca （murca） 过程和核子-核子轫致辐射为主。Friman 和 Maxwell 于 1979 年提供了标准发射速率，有效地基于具有 pion 和 rho 介子交换的手性拉格朗日框架，并辅以 Landau 参数来描述短程相互作用。我们在同一框架内重新评估了这些速率，纠正了几个错误并删除了不必要的简化，特别是 MURCA 中的三角近似——其中质子和轻子的费米动量与中子的费米动量相比可以忽略不计——并量化了它们的重要性。rho 介子交换的影响，以前认为可以抵消干扰效应，实际上非常相关。总的来说，冷却速率降低了 2 倍。我们提供全面的分析公式，涵盖所有贡献，专为直接的数值实现而设计。我们的结果与标准模型以外的物理学研究特别相关，其中新粒子（例如轴子）的发射通常在我们这里采用的相同框架内计算。