Cascade of particles injected as Hawking Radiation from Primordial Black Holes (PBH) can potentially change the cosmic recombination history by ionizing and heating the intergalactic medium, which results in altering the anisotropy spectra of the Cosmic Microwave Background (CMB). In this paper, we study the expected sensitivity of several future CMB experiments in constraining the abundance of PBHs distributed in 10¹⁵∼10¹⁷ g mass window according to four mass functions: the monochromatic, log-normal, power-law and critical collapse models. Our result shows that future experiments, such as CMB-S4 and PICO, can improve the current Planck bounds by about two orders of magnitude. Most regions in PBH parameter space that are allowed by current CMB data, including monochromatically distributed PBHs with mass heavier than 3.8 10¹⁶ g, can be tested by upcoming missions with high significance.

从原始黑洞（PBH）作为霍金辐射注入的粒子级联可以通过电离和加热星系间介质来潜在地改变宇宙复合历史，从而改变宇宙微波背景（CMB）的各向异性光谱。在本文中，我们研究了几个未来 CMB 实验在根据四种质量函数约束分布在 10 ¹⁵ ∼10 ¹⁷ g 质量窗口中的 PBH 丰度的预期灵敏度：单色、对数正态、幂律和临界坍缩模型. 我们的结果表明，未来的实验，如 CMB-S4 和 PICO，可以改进当前的普朗克界大约两个数量级。当前 CMB 数据允许的 PBH 参数空间中的大多数区域，包括质量大于 3.8 10 ¹⁶ g 的单色分布的 PBH，都可以通过即将到来的具有重要意义的任务进行测试。