The Large Hadron Collider (LHC) has confirmed the Higgs mechanism to generate mass in the Standard Model (SM), making it attractive also to consider spontaneous symmetry breaking as the origin of mass for new particles in a dark sector extension of the SM. Such a dark Higgs mechanism may in particular give mass to a dark matter candidate and to the gauge boson mediating its interactions (called dark photon). In this review, we summarize the phenomenology of the resulting dark Higgs boson and discuss the corresponding search strategies with a focus on collider experiments. We consider both the case that the dark Higgs boson is heavier than the SM Higgs boson, in which case leading constraints come from direct searches for new Higgs bosons as well missing-energy searches at the LHC, and the case that the dark Higgs boson is (potentially much) lighter than the SM Higgs boson, such that the maximum sensitivity comes from electron–positron colliders and fixed-target experiments. Of particular experimental interest for both cases is the associated production of a dark Higgs boson with a dark photon, which subsequently decays into SM fermions, dark matter particles or long-lived dark sector states. We also discuss the important role of exotic decays of the SM-like Higgs boson and complementary constraints arising from early-universe cosmology, astrophysics, and direct searches for dark matter in laboratory experiments.

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对撞机中的暗希格斯玻色子

大型强子对撞机 (LHC) 已经证实了标准模型 (SM) 中产生质量的希格斯机制，这使得将自发对称破缺视为 SM 暗区延伸中新粒子的质量起源也很有吸引力。这种暗希格斯机制尤其可以为候选暗物质和介导其相互作用的规范玻色子（称为暗光子）提供质量。在这篇综述中，我们总结了由此产生的暗希格斯玻色子的现象学，并讨论了相应的搜索策略，重点关注对撞机实验。我们考虑暗希格斯玻色子比 SM 希格斯玻色子重的情况，在这种情况下，主要约束来自对新希格斯玻色子的直接搜索以及大型强子对撞机的缺失能量搜索，以及暗希格斯玻色子比 SM 希格斯玻色子重的情况。 （可能）比 SM 希格斯玻色子轻，因此最大灵敏度来自正负电子对撞机和固定目标实验。这两种情况的实验特别感兴趣的是暗希格斯玻色子与暗光子的相关产生，暗光子随后衰变成 SM 费米子、暗物质粒子或长寿命暗扇区状态。我们还讨论了类 SM 希格斯玻色子的奇异衰变的重要作用，以及早期宇宙宇宙学、天体物理学和实验室实验中对暗物质的直接搜索所产生的补充约束。