标题： 类轴子混合暴胀中的原初黑洞和二阶引力波 显示英文标题

标题： Primordial Black Holes and Second-order Gravitational Waves in Axion-like Hybrid Inflation

摘要： 我们研究原初黑洞（PBHs）是否可能由混合暴胀模型中轴子样粒子（ALP）驱动的水坝相变期间产生的大曲率扰动形成$\phi$。 该模型预测谱指数$n_s \simeq 0.964$和张量-标量比$r \simeq 0.003$，与普朗克数据一致，并且可通过下一代宇宙微波背景（CMB）实验如CMB-S4和LiteBIRD进行检验。 我们发现PBH质量以及相关标量诱导引力波（SIGW）谱的峰值与ALP质量相关。 特别是质量范围在$10^{-13}\, M_\odot$的PBH可能构成整个宇宙的暗物质（DM）或其中的重要部分。 此机制预测的二阶引力波处于未来观测站如LISA和ET的灵敏度范围内。 该模型中的典型再加热温度约为$10^6 - 10^7$GeV，与大爆炸核合成（BBN）约束一致。 显示英文摘要

摘要： We investigate the possibility that primordial black holes (PBHs) can be formed from large curvature perturbations generated during the waterfall phase transition in a hybrid inflation model driven by an axion-like particle (ALP) $\phi$. The model predicts a spectral index $n_s \simeq 0.964$ and a tensor-to-scalar ratio $r \simeq 0.003$, in agreement with Planck data and potentially testable by next generation cosmic microwave background (CMB) experiments such as CMB-S4 and LiteBIRD. We find that the PBH mass and the peak of the associated scalar-induced gravitational wave (SIGW) spectrum are correlated with the ALP mass. In particular, PBHs in the mass range $10^{-13}\, M_\odot$ can constitute either the entire dark matter (DM) content of the universe or a significant fraction of it. The predicted second-order GWs from this mechanism are within the sensitivity reach of future observatories like LISA and ET. The typical reheating temperature in the model is around $10^6 - 10^7$ GeV is consistent with Big Bang Nucleosynthesis (BBN) constraints.