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arXiv 2302.02735hep-phhep-ex
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2HDM+$a$ 模型中的长寿命粒子唯象学

Long-lived particle phenomenology in the 2HDM+$a$ model

Ulrich Haisch, Luc Schnell

AI总结:

本文指出在混合角极小且暗物质扇区解耦或不可及的 2HDM+$a$ 模型中会出现偏离顶点的 Higgs 衰变信号,利用 LHC Run II 数据排除了特定混合角范围,并证明该参数选择能同时解释暗物质丰度。

摘要:

偏离初级相互作用顶点的 Higgs 衰变是一种引人注目的实验特征,ATLAS、CMS 和 LHCb 合作组正在积极寻找此类信号。我们指出,如果两个 CP 奇弱自旋 0 本征态的混合角 $θ$ 极小,且暗物质(DM)扇区要么解耦,要么在运动学上不可及,则 2HDM+$a$ 模型中会出现此类信号。利用两个合适的基准情景,我们确定了现有 LHC 对 Higgs 衰变中长寿命粒子(LLPs)的搜索对 2HDM+$a$ 模型参数空间所施加的限制。我们发现,根据自旋 0 态的精确质量谱,基于 LHC Run II 数据,可以排除大约在 $10^{-8}$ 到 $10^{-5}$ 量级的混合角 $θ$。这一发现强调了寻找位移特征在约束 2HDM+$a$ 模型参数空间方面所能发挥的独特作用。此外还讨论了随之而来的 DM 唯象学。特别是,我们表明,导致有趣 LLP 唯象学的参数选择能够同时解释当今宇宙中观测到的 DM 丰度。

英文摘要:

Higgs decays displaced from the primary interaction vertex represent a striking experimental signature that is actively searched for by the ATLAS, CMS and LHCb collaborations. We point out that signals of this type appear in the context of the 2HDM+$a$ model if the mixing angle $θ$ of the two CP-odd weak spin-0 eigenstates is tiny and the dark matter (DM) sector is either decoupled or kinematically inaccessible. Utilising two suitable benchmark scenarios, we determine the constraints on the parameter space of the 2HDM+$a$ model that are set by the existing LHC searches for long-lived particles (LLPs) in Higgs decays. We find that depending on the precise mass spectrum of the spin-0 states, mixing angles $θ$ in the ballpark of a few $10^{-8}$ to $10^{-5}$ can be excluded based on LHC Run II data. This finding emphasises the unique role that searches for displaced signatures can play in constraining the parameter space of the 2HDM+$a$ model. The ensuing DM phenomenology is also discussed. In particular, we show that parameter choices leading to an interesting LLP phenomenology can simultaneously explain the DM abundance observed in today's Universe.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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