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arXiv 1304.2196astro-ph.COgr-qchep-th
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耦合暗物质的宇宙学效应

Cosmological effects of coupled dark matter

Sophie C. F. Morris, Anne M. Green, Antonio Padilla, Ewan R. M. Tarrant

摘要:

人们已经研究了许多包含不止一种暗物质的模型,其中一些模型将冷暗物质(CDM)耦合到光标量场。在这样做的时候,我们引入了额外的长程力,如果不适当地解释,这反过来又会显著影响我们对宇宙学参数的估计。因此,研究这些模型及其产生的宇宙学意义是很重要的。我们提出了一个模型,其中一小部分的总冷暗物质密度耦合到一个标量场。我们研究了背景和微扰的演化,并计算了由此产生的宇宙微波背景各向异性谱。耦合到标量场的暗物质的比例越大,耦合强度越强,背景演化与LCDM的偏差越大。以前的工作,与一个单一的耦合暗物质物种,发现了一个上限的耦合强度为O(0.1)。我们发现,与此幅度的耦合超过一半的暗物质可以耦合到一个标量场,而不会产生任何显着偏离LCDM。

英文摘要:

Many models have been studied that contain more than one species of dark matter and some of these couple the Cold Dark Matter (CDM) to a light scalar field. In doing this we introduce additional long range forces, which in turn can significantly affect our estimates of cosmological parameters if not properly accounted for. It is, therefore, important to study these models and their resulting cosmological implications. We present a model in which a fraction of the total cold dark matter density is coupled to a scalar field. We study the background and perturbation evolution and calculate the resulting Cosmic Microwave Background anisotropy spectra. The greater the fraction of dark matter coupled to the scalar field and the stronger the coupling strength, the greater the deviation of the background evolution from LCDM. Previous work, with a single coupled dark matter species, has found an upper limit on the coupling strength of order O(0.1). We find that with a coupling of this magnitude more than half the dark matter can be coupled to a scalar field without producing any significant deviations from LCDM.

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