arXiv 2108.033172021-08hep-thastro-ph.COhep-ph

黑暗辐射和黑暗阶段

Dark Radiation and the Hagedorn Phase

Andrew R. Frey, Ratul Mahanta, Anshuman Maharana

备注：: v2. 7pp double-columned, somewhat improved discussion, minor clarifications, matches published version up to typography/formatting
发表信息：: Phys. Rev. D 105, 066007 (2022)
DOI：: 10.1103/PhysRevD.105.066007

摘要：

我们指出，如果与标准模型自由度相关的扇区在早期宇宙中进入了开弦哈格多恩相，而暗辐射扇区不是这个等离子体的一部分，那么这可能导致暗辐射中可观测到的$ΔN_{\text{eff}}$（额外的类中微子物质的数量）的低值。对于显式分析，我们专注于翘曲弦紧致与标准模型自由度在底部的翘曲喉。如果膨胀期间的哈勃尺度高于与喉部相关的扭曲弦尺度，那么标准模型扇区将进入哈格多恩阶段。在这种情况下，从暗辐射的角度来看，体轴子不再是危险的。虽然这篇文章的重点是翘曲紧致化，但基本思想可以与早期宇宙进入哈格多恩阶段的任何场景相关。

英文摘要：

We point out that if the sector associated with the Standard Model degrees of freedom entered an open string Hagedorn phase in the early universe while the dark radiation sector was not part of this plasma, then this can lead to low values of the observable $ΔN_{\text{eff}}$ (number of additional neutrinolike species) from the dark radiation. For explicit analysis, we focus on warped string compactifications with the Standard Model degrees of freedom at the bottom of a warped throat. If the Hubble scale during inflation is above the warped string scale associated with the throat, then the Standard Model sector will enter the Hagedorn phase. In this scenario, bulk axions are no longer dangerous from the point of view of dark radiation. While this article focuses on warped compactifications, the basic idea can be relevant to any scenario where the early universe entered a Hagedorn phase.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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