论文标题
精确宇宙学时代的原始Lepton不对称：BBN和CMB的当前状态和未来敏感性
Primordial lepton asymmetries in the precision cosmology era: Current status and future sensitivities from BBN and the CMB
论文作者
论文摘要
皇后调查使用了新的非常贫穷的系统的新样本，最近报道了原始的氦气丰度比标准的大爆炸核合成（BBN）场景的预测小3σ$ 3。该测量值可以解释为电子中微子风味中原始的麻风不对称的提示。在女皇的结果中，我们使用Planck的宇宙微波背景（CMB）数据进行了对Lepton不对称的全面分析。假设我们的宇宙中没有暗辐射，我们发现电子中微子化学势$ξ_{ν_e} = 0.043 \ pm 0.015 $，它从零偏离$2.9σ$。如果没有对宇宙中深色辐射的丰度做出的假设，则化学电位为$ξ_{ν_e} = 0.046 \ pm 0.021 $，从零偏离$2.2σ$。我们还发现，该结果对核反应速率的选择不敏感。如果真实的氦气丰度对应于Empress的中心价值，那么Simons天文台和CMB-S4的未来CMB观察结果将分别提高非零Lepton不对称的意义，分别为$4σ$和$5σ$，假设没有深色辐射，或者在没有对$3σ$上进行$3σ$，则在没有假设的情况下，就会被纳入深度辐射。
Using a new sample of extremely metal poor systems, the EMPRESS survey has recently reported a primordial helium abundance that is $3σ$ smaller than the prediction from the standard big bang nucleosynthesis (BBN) scenario. This measurement could be interpreted as a hint for a primordial lepton asymmetry in the electron neutrino flavor. Motivated by the EMPRESS results, we present a comprehensive analysis of the lepton asymmetry using measurements of the abundances of primordial elements, along with cosmic microwave background (CMB) data from Planck. Assuming that there is no dark radiation in our Universe, we find an electron neutrino chemical potential $ξ_{ν_e} = 0.043 \pm 0.015$, which deviates from zero by $2.9σ$. If no assumption is made on the abundance of dark radiation in the Universe, the chemical potential is $ξ_{ν_e} = 0.046 \pm 0.021$, which deviates from zero by $2.2σ$. We also find that this result is rather insensitive to the choice of nuclear reaction rates. If the true helium abundance corresponds to the EMPRESS central value, future CMB observations from the Simons Observatory and CMB-S4 will increase the significance for a nonzero lepton asymmetry to $4σ$ and $5σ$ respectively, assuming no dark radiation, or to $3σ$ when no assumption is made on the abundance of dark radiation.
