发表机构
Sungkyunkwan University; Indian Institute of Technology Goa（成均馆大学; 印度理工学院果阿分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对轻暗物质的热不足与CMB约束问题，提出含类矢量费米子的标量门户模型，利用BBN前刚性流体主导的非标准宇宙学解决遗迹密度问题，建立粒子参数与引力波信号的关联。
AI 中文摘要
直接探测实验缺乏信号，使经典弱相互作用大质量粒子（WIMP）范式面临严峻压力，推动研究转向亚吉电子伏特轻暗物质（LDM）领域。然而，实现可探测的LDM相互作用率通常需要与可见部分的大耦合，这在标准宇宙学中会导致暗物质遗迹密度严重热不足。此外，具有矢量媒介子的LDM模型因后期能量注入面临来自宇宙微波背景（CMB）的严格约束。本研究提出一种最小标量门户扩展模型，包含类矢量费米子暗物质候选体，其通过固有的p波湮灭抑制自然规避CMB约束。为同时实现正确的遗迹密度和大直接探测耦合，我们采用大爆炸核合成（BBN）前由刚性流体（w > 1/3）主导的非标准宇宙学。该时期增强的哈勃膨胀触发早期暗物质退耦，成功恢复渐近遗迹丰度。关键的是，BBN前的刚性相使在BBN前重新进入视界的暴胀引力波发生严重蓝移，在随机引力波背景上留下独特的高频倾斜。我们建立了非标准膨胀历史、未来地面直接探测实验可验证的粒子物理参数与LISA、DECIGO等即将到来的天基干涉仪可观测的独特引力波信号之间的稳健关联。该框架凸显多信使观测如何同时探测暗 sector和宇宙的BBN前热历史。
英文摘要
The lack of signals in direct detection experiments has placed the canonical Weakly Interacting Massive Particle (WIMP) paradigm under severe tension, motivating a shift toward the sub-GeV Light Dark Matter (LDM) regime. However, realizing detectable LDM interaction rates typically requires large couplings to the visible sector, which leads to a severe thermal underabundance of the dark matter relic density within standard cosmology. Furthermore, LDM models featuring vector mediators face stringent constraints from the Cosmic Microwave Background (CMB) due to late-time energy injection. In this work, we propose a minimal scalar portal extension featuring a vector-like fermion dark matter candidate, which naturally evades CMB bounds via inherent p-wave annihilation suppression. To simultaneously achieve the correct relic density and large direct-detection couplings, we invoke a pre-Big Bang Nucleosynthesis (BBN) non-standard cosmology dominated by a stiff fluid ($w > 1/3$). The enhanced Hubble expansion during this epoch triggers an early dark matter freeze-out, successfully rescuing the asymptotic relic abundance. Crucially, this stiff pre-BBN phase heavily blue-shifts inflationary gravitational waves that re-enter the horizon prior to BBN, imprinting a distinct high-frequency tilt on the stochastic gravitational wave background. We establish a robust correlation between the non-standard expansion history, the particle physics parameters verifiable in future terrestrial direct detection experiments, and the unique gravitational wave signatures observable by forthcoming space-based interferometers like LISA and DECIGO. This framework highlights how multi-messenger observations can concurrently probe the dark sector and the pre-BBN thermal history of the Universe.
Comments25 pages, 8 captioned figures;
