Sterile neutrinos with a mass in the eV range have been invoked as a possible explanation of a variety of short baseline (SBL) neutrino oscillation anomalies. However, if one considers neutrino oscillations between active and sterile neutrinos, such neutrinos would have been fully thermalised in the early universe, and would be therefore in strong conflict with cosmological bounds. In this study we first update cosmological bounds on the mass and energy density of eV-scale sterile neutrinos. We then perform an updated study of a previously proposed model in which the sterile neutrino couples to a new light pseudoscalar degree of freedom. Consistently with previous analyses, we find that the model provides a good fit to all cosmological data and allows the high value of $H_0$ measured in the local universe to be consistent with measurements of the cosmic microwave background. However, new high $\ell$ polarisation data constrain the sterile neutrino mass to be less than approximately 1~eV in this scenario. Finally, we combine the cosmological bounds on the pseudoscalar model with a Bayesian inference analysis of SBL data and conclude that only a sterile mass in a narrow range around 1~eV remains consistent with both cosmology and SBL data.

中文翻译：

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无菌中微子自相互作用：H0 张力和短基线异常

质量在 eV 范围内的无菌中微子已被用作各种短基线 (SBL) 中微子振荡异常的可能解释。然而，如果考虑活跃中微子和惰性中微子之间的中微子振荡，这样的中微子在早期宇宙中会被完全热化，因此会与宇宙学界限发生强烈冲突。在这项研究中，我们首先更新了 eV 级无菌中微子的质量和能量密度的宇宙学界限。然后，我们对先前提出的模型进行了更新研究，在该模型中，无菌中微子耦合到新的轻伪标量自由度。与之前的分析一致，我们发现该模型为所有宇宙学数据提供了良好的拟合，并允许在本地宇宙中测量的 $H_0$ 的高值与宇宙微波背景的测量结果一致。然而，在这种情况下，新的高极化数据限制了惰性中微子质量小于大约 1~eV。最后，我们将伪标量模型的宇宙学界限与 SBL 数据的贝叶斯推理分析相结合，得出结论，只有在 1~eV 左右的狭窄范围内的无菌质量与宇宙学和 SBL 数据保持一致。