A weakly interacting massive particle (WIMP) is a leading candidate of the dark matter. The WIMP dark matter abundance is determined by the freeze-out mechanism. Once we know the property of the WIMP particle such as the mass and interaction, we can predict the dark matter abundance. There are, however, several uncertainties in the estimation of the WIMP dark matter abundance. In this work, we focus on the effect from Standard Model thermodynamics. We revisit the estimation of the WIMP dark matter abundance and its uncertainty due to the equation of state (EOS) in the Standard Model. We adopt the up-to-date estimate of the EOS of the Standard Model in the early Universe and find nearly 10% difference in the 1-1000 GeV dark matter abundance, compared to the conventional estimate of the EOS.

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精确的 WIMP 暗物质丰度和标准模型热力学

弱相互作用大质量粒子（WIMP）是暗物质的主要候选者。WIMP 暗物质丰度由冻结机制决定。一旦我们知道了 WIMP 粒子的质量和相互作用等特性，我们就可以预测暗物质丰度。然而，对 WIMP 暗物质丰度的估计存在一些不确定性。在这项工作中，我们关注标准模型热力学的影响。由于标准模型中的状态方程 (EOS)，我们重新审视了 WIMP 暗物质丰度的估计及其不确定性。我们采用了早期宇宙中标准模型的 EOS 的最新估计，发现 1-1000 GeV 暗物质丰度与 EOS 的常规估计相比有近 10% 的差异。