Non-Gaussian isocurvature perturbations in dark radiation
Non-Gaussian isocurvature perturbations in dark radiation
复制标题
暗辐射中的非高斯等曲率扰动
DOI：
10.1088/1475-7516/2012/07/037
复制
发表时间：
2012
影响因子：
6.4
通讯作者：
関口豊和
中科院分区：
文献类型：
--
作者：
川上悦子;川崎雅裕;宮本幸一;中山和則;関口豊和
我们研究了暗辐射中等曲率扰动的非高斯性质，其中包括活动中微子和额外的轻物种，如果存在的话。首先，我们推导出的原始扰动的曲率和暗辐射等曲率扰动的混合物的双谱的表达式。我们还讨论了在我们的模型中产生的CMB双谱，并预测CMB约束的非线性参数的基础上的Fisher矩阵分析。提出了一些具体的粒子物理模型，其中可能产生额外轻物质的大等曲率扰动和/或中微子密度等曲率扰动及其非高斯性。因此，在暗辐射等曲率扰动的非高斯检测将给我们一个机会，以确定额外的轻物种和轻子不对称性的起源。
We study non-Gaussian properties of the isocurvature perturbations in the dark radiation, which consists of the active neutrinos and extra light species, if exist. We first derive expressions for the bispectra of primordial perturbations which are mixtures of curvature and dark radiation isocurvature perturbations. We also discuss CMB bispectra produced in our model and forecast CMB constraints on the non-linearity parameters based on the Fisher matrix analysis. Some concrete particle physics motivated models are presented in which large isocurvature perturbations in extra light species and/or the neutrino density isocurvature perturbations as well as their non-Gaussianities may be generated. Thus detections of non-Gaussianity in the dark radiation isocurvature perturbation will give us an opportunity to identify the origin of extra light species and lepton asymmetry.