论文标题
BBN对深色辐射等效性的约束
BBN constraints on dark radiation isocurvature
论文作者
论文摘要
在早期宇宙中完全与标准模型完全脱钩的暗辐射的存在开放了相关的暗辐射等效模式的可能性。我们表明，由于$ n _ {\ rm eff} $在大爆炸核合成期间的空间变化，黑暗辐射等效性的存在导致氦气和氘的原始丰度的空间变化。我们使用结果来限制在秤上的这种等异生模式的存在，以降低到$ \ sim 1 $ mpc量表。通过测量不同星系中原始氦与氢和氢比的过剩方差，我们将银河系中平均等离子的差异限制为小于$ 0.13/δ\ bar {n} _ {\ rm eff} $ 95 \％置信度。这里$Δ\ bar {n} _ {\ rm eff} $是由于附加的深色辐射组件，$ n _ {\ rm eff} $中空间平均的增加。
The existence of dark radiation that is completely decoupled from the standard model in the early Universe leaves open the possibility of an associated dark radiation isocurvature mode. We show that the presence of dark radiation isocurvature leads to spatial variation in the primordial abundances of helium and deuterium due to spatial variation in $N_{\rm eff}$ during Big Bang nucleosynthesis. We use the result to constrain the existence of such an isocurvature mode on scales down to $\sim 1$ Mpc scales. By measuring the excess variance in the primordial helium to hydrogen and deuterium to hydrogen ratio in different galaxies, we constrain the variance in average isocurvature in a galaxy to be less than $0.13/Δ\bar{N}_{\rm eff}$ at 95\% confidence. Here $Δ\bar{N}_{\rm eff}$ is the spatially averaged increase in $N_{\rm eff}$ due to the additional dark radiation component.
