arXiv 1503.060122015-03astro-ph.CO

CMB和BAO的基本常数是什么？

Which Fundamental Constants for CMB and BAO?

James Rich

发表信息：: A&A 584, A69 (2015)
DOI：: 10.1051/0004-6361/201526847

摘要：

我们使用胡等人的三尺度框架来说明宇宙微波背景各向异性谱如何依赖于基本常数。正如预期的那样，光谱只取决于常数的\emph{dimensionless}组合，我们强调的是，这使得宇宙学观测值普遍成立。我们的分析表明，CMB谱的形状主要是由$α^2m_e/m_p$和质子CDM粒子的质量比，$m_p/\mchi$。到最后一个散射表面的距离取决于$Gm_p\mchi/\hbar c$，因此已发表的CMB观测常数随时间变化的极限隐含地假设了这个量的时间无关性，以及假设一个平坦的\lcdm ~宇宙学模型。另一方面，低红移的BAO、$H_0$和重子质量分数的测量可以与CMB谱的\emph{shape}结合起来，得到的信息在很大程度上与这些假设无关。特别是，我们表明，预重组值的$G\mchi^2/\hbar c$，$m_p/\mchi$和$α^2m_e/m_p$是等于它们的当前值在一个精确度为$\sim15\%$。

英文摘要：

We use the three-scale framework of Hu et al. to show how the Cosmic Microwave Background anisotropy spectrum depends on the fundamental constants. As expected, the spectrum depends only on \emph{dimensionless} combinations of the constants, and we emphasize the points that make this generally true for cosmological observables. Our analysis suggests that the CMB spectrum shape is mostly determined by $α^2m_e/m_p$ and the proton-CDM-particle mass ratio, $m_p/\mchi$. The distance to the last-scattering surface depends on $Gm_p\mchi/\hbar c$, so published CMB observational limits on time variations of the constants implicitly assume the time-independence of this quantity, as well as assuming a flat-\lcdm~cosmological model. On the other hand, low-redshift BAO, $H_0$ and baryon-mass-fraction measurements can be combined with the \emph{shape} of the CMB spectrum to give information that is largely independent of these assumptions. In particular we show that the pre-recombination values of $G\mchi^2/\hbar c$, $m_p/\mchi$ and $α^2m_e/m_p$ are equal to their present values at a precision of $\sim15\%$.

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