标题： 引力波与暗物质在规范两希格斯双重模型中的研究 显示英文标题

标题： Gravitational Waves and Dark Matter in the Gauged Two-Higgs Doublet Model

摘要： 我们研究了在规范双希格斯二重态模型（G2HDM）框架下，早期宇宙中强一阶电弱相变的可能性，并探讨其通过随机引力波信号的可探测性。 G2HDM引入了标准模型电弱规范群的暗态副本，诱导了一个意外的$Z_2$对称性，这不仅导致了树级的简单标量势，还提供了一个有说服力的矢量型暗物质候选者。 利用有效势中的高温展开，该展开表现出规范不变性，我们发现该模型中可能存在两步相变模式，在电弱尺度温度下第二步发生强一阶相变。 来自大型强子对撞机（LHC）的对撞数据在约束有利于这种两步相变的参数空间中起着关键作用。 此外，满足成核条件需要隐藏区中标量玻色子的质量与电弱尺度一致，可能由未来的对撞机探测器探测。 与相变相关的随机引力波能量谱被计算出来。 结果表明，未来的探测器如BBO、LISA、DECIGO、天琴和太极有可能探测到由一阶相变产生的引力波信号。 此外，我们发现引力波探测的参数空间也可以在未来暗物质直接探测实验中进行搜索，特别是那些专为亚GeV范围内的暗物质质量设计并使用超流氦靶探测器的实验。 显示英文摘要

摘要： We investigate the possibility of a strong first-order electroweak phase transition during the early universe within the framework of the gauged two-Higgs doublet model (G2HDM) and explore its detectability through stochastic gravitational wave signals. The G2HDM introduces a dark replica of the Standard Model electroweak gauge group, inducing an accidental $Z_2$ symmetry which not only leads to a simple scalar potential at tree-level but also offers a compelling vectorial dark matter candidate. Using the high temperature expansion in the effective potential that manifests gauge invariance, we find a possible two-step phase transition pattern in the model with a strong first-order transition occurring in the second step at the electroweak scale temperature. Collider data from the LHC plays a crucial role in constraining the parameter space conducive to this two-step transition. Furthermore, satisfying the nucleation condition necessitates the masses of scalar bosons in the hidden sector to align with the electroweak scale, potentially probed by future collider detectors. The stochastic gravitational wave energy spectrum associated with the phase transition is computed. The results indicate that forthcoming detectors such as BBO, LISA, DECIGO, TianQin and Taiji could potentially detect the gravitational wave signals generated by the first-order phase transition. Additionally, we find that the parameter space probed by gravitational waves can also be searched for in future dark matter direct detection experiments, in particular those designed for dark matter masses in the sub-GeV range using the superfluid Helium target detectors.