Kaluza-Klein Towers in the Early Universe: Phase Transitions, Relic Abundances, and Applications to Axion Cosmology
Kaluza-Klein Towers in the Early Universe: Phase Transitions, Relic Abundances, and Applications to Axion Cosmology
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早期宇宙中的卡鲁扎-克莱因塔：相变、遗迹丰度以及轴子宇宙学的应用
DOI：
10.1103/physrevd.95.123539
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发表时间：
2016
影响因子：
5
通讯作者：
B. Thomas
中科院分区：
文献类型：
--
作者：
K. Dienes;Jeff Kost;B. Thomas
我们研究了存在质量生成相变的Kaluza-Klein （KK）标量场塔的早期宇宙宇宙学，重点研究了总塔能量密度（或遗迹丰度）的时间发展及其在不同KK模式中的分布。我们发现这两个特征对相变的细节非常敏感，并且可以以各种方式表现，这对后期宇宙学具有重要意义。特别是，我们发现相变的时间特性和它产生的混合之间的相互作用对后期丰度的增强和抑制负责，有时是许多数量级。我们绘制出完整的模型参数空间，并确定传统的解析近似在哪里有效，在哪里失效。在后一种情况下，我们还提供了新的解析近似，成功地模拟了我们的结果。最后，我们将这种机制应用于体中轴子样场的例子，将这些现象映射到扩大的轴子参数空间上，超出了标准处理所能达到的范围。我们分析的一个重要副产品是KK理论的另一种“基于紫外线的”有效截断的发展，它具有许多有趣的理论性质，将其与通常在额外维度文献中使用的更传统的“基于红外的”截断区分开来。
We study the early-universe cosmology of a Kaluza-Klein (KK) tower of scalar fields in the presence of a mass-generating phase transition, focusing on the time-development of the total tower energy density (or relic abundance) as well as its distribution across the different KK modes. We find that both of these features are extremely sensitive to the details of the phase transition and can behave in a variety of ways significant for late-time cosmology. In particular, we find that the interplay between the temporal properties of the phase transition and the mixing it generates are responsible for both enhancements and suppressions in the late-time abundances, sometimes by many orders of magnitude. We map out the complete model parameter space and determine where traditional analytical approximations are valid and where they fail. In the latter cases we also provide new analytical approximations which successfully model our results. Finally, we apply this machinery to the example of an axion-like field in the bulk, mapping these phenomena over an enlarged axion parameter space that extends beyond those accessible to standard treatments. An important by-product of our analysis is the development of an alternate "UV-based" effective truncation of KK theories which has a number of interesting theoretical properties that distinguish it from the more traditional "IR-based" truncation typically used in the extra-dimension literature.