标题： 哈勃张力：长寿命粒子产生的相对论暗物质产率 显示英文标题

标题： The Hubble Tension: Relativistic Dark Matter Production from Long-lived Particles

摘要： 哈勃常数的直接测量与源于宇宙微波背景探测器的结果之间的张力引发了许多研究。 宇宙学与粒子物理学之间的联系被证明是一种解决哈勃张力的有价值方法。 特别是，增加早期宇宙中相对论自由度的数量有助于缓解这一问题。 在这项工作中，我们写下描述与中微子相关的相对论暗物质产生的有效场理论，从而导致更大的$H_0$。 我们推导出限制有效能量尺度的界限，该尺度控制着这种相对论暗物质的产生，作为费米子、矢量和标量暗物质场的质量函数。 特别是，标量暗物质粒子在增加相对论物种的有效数量方面更为有效。 此外，如果它们具有弱尺度质量，则为了缓解哈勃张力，暗物质的相对论产生应由普朗克尺度的有效算符来控制。 显示英文摘要

摘要： The tension between direct measurements of the Hubble constant and those stemming from Cosmic Microwave Background probes has triggered a multitude of studies. The connection between cosmology and particle physics has shown to be a valuable approach to addressing the Hubble tension. In particular, increasing the number of relativistic degrees of freedom in the early universe helps alleviate the problem. In this work, we write down effective field theory describing relativistic dark matter production in association with neutrinos leading to a larger $H_0$. We derive limits on the effective energy scale that governs this relativistic production of dark matter as a function of the dark matter mass for fermion, vector, and scalar dark matter fields. In particular, scalar dark matter particles are more effective in increasing the effective number of relativistic species. Also, if they have weak scale masses, then the relativistic production of dark matter should be governed by Planck scale effective operators in order to alleviate the Hubble tension.