连接矢量型缪子、pNGB暗物质与电弱相变：通过对撞机与引力波
Connecting Vector-like Muons, pNGB Dark Matter and Electroweak Phase Transition through Collider and Gravitational Wave
- Indian Institute of Technology Guwahati（印度理工学院古瓦哈提分校）
- Gokhale Memorial Girls’ College（戈卡尔纪念女子学院）
- Shanghai Institute for Advanced Studies（上海高等研究院）
- University of Science and Technology of China（中国科学技术大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究提出标准模型扩展，引入pNGB暗物质和矢量型缪子，通过缪子对撞机增强产生并分析强一阶电弱相变，产生可观测引力波信号，实现多探针互补。
AI中文摘要：
我们研究标准模型的一种扩展，包含两个复标量单态$S_2$和$S_3$，分别带有$\nmathbb{Z}_2$和$\nmathbb{Z}_3$电荷，以及一个缪子亲和的矢量型轻子$\psi$，其携带与$S_3$相同的$\nmathbb{Z}_3$电荷。与$\nmathbb{Z}_2$扇区关联的赝标量由于势能的CP对称性而保持稳定，并作为暗物质（DM）候选者，其质量通过相应的全局$U(1)$对称性软破缺产生。矢量型缪子与$\nmathbb{Z}_3$标量耦合，使第二个赝标量不稳定，从而实现有效的单组分pNGB暗物质场景。pNGB特性强烈抑制了树级自旋无关直接探测截面，而可行的参数区域重现了观测到的遗迹丰度并满足LHC单喷注约束。我们进一步计算了暗物质-核子散射的单圈贡献，发现所得截面仍低于当前实验极限，同时可能被未来的直接探测实验所触及。在多TeV缪子对撞机上，标量介导的$t$道过程可显著增强矢量型缪子对的产生。我们对未来质心能量为3 TeV的缪子对撞机进行了详细的多变量分析。我们还确定了表现出强一阶电弱相变（SFOEWPT）且具有成功气泡成核的可行基准点，这些点可以产生潜在可观测的随机引力波（GW）信号。这些结果凸显了暗物质搜索、缪子对撞机探测和SFOEWPT之间的互补性，所产生的GW信号为扩展标量扇区提供了额外探针。
英文摘要：
We study an extension of the Standard Model with two complex scalar singlets, $S_2$ and $S_3$, charged under $\mathbb{Z}_2$ and $\mathbb{Z}_3$, respectively, and a muon-philic vector-like lepton $ψ$ carrying the same $\mathbb{Z}_3$ charge as $S_3$. The pseudoscalar associated with the $\mathbb{Z}_2$ sector remains stable due to the CP symmetry of the potential and serves as the dark matter (DM) candidate, with its mass generated through the corresponding soft breaking of the global $U(1)$ symmetry. The vector-like muon couples to the $\mathbb{Z}_3$ scalar and renders the second pseudoscalar unstable, thereby realizing an effectively single-component pNGB DM scenario. The pNGB nature strongly suppresses the tree-level spin-independent direct-detection cross section, while viable parameter regions reproduce the observed relic abundance and satisfy LHC monojet constraints. We further compute the one-loop contribution to DM-nucleon scattering and find that the resulting cross section remains below current experimental limits while being potentially accessible to future direct-detection experiments. At a multi-TeV muon collider, scalar mediated $ t$-channel processes can significantly enhance vector-like-muon pair production. We perform a detailed multivariate analysis for a future muon collider at 3 TeV center-of-mass energy. We also identify viable benchmark points exhibiting strong first-order electroweak phase transitions (SFOEWPT) with successful bubble nucleation, which can generate potentially observable stochastic gravitational wave (GW) signals. These results highlight the complementarity of dark matter searches, muon-collider probes, and SFOEWPT, with the resulting GW signals providing an additional probe of the extended scalar sector.
