Free-streaming and coupled dark radiation isocurvature perturbations: constraints and application to the Hubble tension
Free-streaming and coupled dark radiation isocurvature perturbations: constraints and application to the Hubble tension
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自由流和耦合暗辐射等曲率扰动：哈勃张力的约束和应用
DOI：
10.1088/1475-7516/2022/05/014
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发表时间：
2022
影响因子：
6.4
通讯作者：
Tsai, Yuhsin
中科院分区：
文献类型：
--
作者：
Ghosh, Subhajit;Kumar, Soubhik;Tsai, Yuhsin
暗辐射（DR）作为一种新的物理候选者出现在标准模型之外的各种场景中。虽然经常假设DR中的扰动是绝热的，但如果在暴胀期间存在多个场，并且其衰变产物并不都彼此热化，则它们可以容易地具有等曲率分量。通过实施适当的等曲率初始条件（IC），我们仅从普朗克2018年的完整数据中推导出对不相关和相关DR密度等曲率扰动的约束，并与其他宇宙学数据集相结合。我们对自由流DR（FDR）的研究更新和推广了现有的中微子密度等曲率扰动的限制，包括不同数量的相对论自由度，并耦合DR（CDR）等曲率，我们推导出第一个界限。我们还表明，CDR质量新的物理效应相比，FDR。一个这样的效果是，对于等曲率IC，FDR与CDR相比产生更大的CMB各向异性-与绝热情况相反。更一般地，我们发现DR等曲率光谱的蓝色倾斜是优选的。这导致了一个更大的哈勃常数值相比，标准的CDM+宇宙学与绝热光谱和松弛的张力。
Dark radiation (DR) appears as a new physics candidate in various scenarios beyond the Standard Model. While it is often assumed that perturbations in DR are adiabatic, they can easily have an isocurvature component if more than one field was present during inflation, and whose decay products did not all thermalize with each other. By implementing the appropriate isocurvature initial conditions (IC), we derive the constraints on both uncorrelated and correlated DR density isocurvature perturbations from the full Planck 2018 data alone, and also in combination with other cosmological data sets. Our study on free-streaming DR (FDR) updates and generalizes the existing bound on neutrino density isocurvature perturbations by including a varying number of relativistic degrees of freedom, and for coupled DR (CDR) isocurvature, we derive the first bound. We also show that for CDR qualitatively new physical effects arise compared to FDR. One such effect is that for isocurvature IC, FDR gives rise to larger CMB anisotropies compared to CDR -- contrary to the adiabatic case. More generally, we find that a blue-tilt of DR isocurvature spectrum is preferred. This gives rise to a larger value of the Hubble constantcompared to the standardCDM+cosmology with adiabatic spectra and relaxes thetension.
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DOI：
--
发表时间：
2011-04
期刊：
arXiv: Instrumentation and Methods for Astrophysics
影响因子：
--
作者：
J. Lesgourgues
通讯作者：
J. Lesgourgues
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影响因子：
5
作者：
D. Langlois;F. Vernizzi
通讯作者：
F. Vernizzi
隐藏的暗物质扇区、暗辐射和宇宙微波背景
DOI：
--
发表时间：
2015
期刊：
影响因子：
--
作者：
Z. Chacko;Yanou Cui;Sungwoo Hong;Takemichi Okui
通讯作者：
Takemichi Okui
影响因子：
5
作者：
C. Kreisch;F. Cyr-Racine;O. Dor'e
通讯作者：
C. Kreisch;F. Cyr-Racine;O. Dor'e
DOI：
10.3847/2041-8213/ac5c5b
发表时间：
2021-12
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
A. Riess;W. Yuan;L. Macri;D. Scolnic;D. Brout;S. Casertano;David O. Jones;Y. Murakami;G. Anand
通讯作者：
A. Riess;W. Yuan;L. Macri;D. Scolnic;D. Brout;S. Casertano;David O. Jones;Y. Murakami;G. Anand