LZ暗物质信号的多信使与古探测器探测
A Common $\sim$55 GeV Inelastic Dark Matter Origin of the LZ, Fermi-LAT, and AMS-02 Excesses and Paleo-Detector Prospects
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- Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）
- University of Science and Technology of China（中国科学技术大学）
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中文总结 AI 辅助
本文提出轻子恐惧非弹性暗物质模型解释LZ实验2.6σ异常，并通过多信使分析和古探测器预测为该模型提供验证途径。
中文摘要 AI 辅助
LUX-ZEPLIN合作组最近在核反冲能量248 keV处报告了一个2.6σ的超额信号，这对标准弹性WIMP范式提出了挑战。我们证明，一个具有矢量介质的轻子恐惧非弹性暗物质模型能够自然地解释这一异常，同时规避所有低能直接探测约束。可行的参数空间具有m_χ1>100 GeV和质量劈裂δ~200-300 keV的特征。我们的多信使分析揭示，无论是重（10 GeV）还是轻（10 MeV）介质场景，都无法重现费米-LAT银河系中心超额信号，而中微子通量与IceCube限制保持一致。两种场景都预测在含铅古探测器中的反冲轨迹接近80 nm。在乐观的铀-238浓度为10^-12 g/g时，10 mg·Gyr的暴露量即使在天体物理信号可忽略的情况下也能产生超过估计背景的超额信号。LZ异常如果得到确认，将指向一个具有非弹性跃迁和轻子恐惧耦合的暗扇区，而古探测器则提供确凿证据。
英文摘要
We investigate the 248~keV nuclear recoil excess reported by LUX-ZEPLIN (LZ) in a leptophobic inelastic dark matter framework, in which the mass splitting naturally suppresses low-energy recoils. We find two viable branches, including the endothermic solution with a high dark matter mass $m_χ\gtrsim400$~GeV and the exothermic one with a mass of tens GeV. Remarkably, the exothermic dark matter scenario with $m_χ\sim55$~GeV can simultaneously account for the LZ excess, the Galactic Center GeV gamma-ray excess, and the AMS-02 antiproton excess. The favored annihilation cross-section is slightly below the one required for the observed relic abundance, resulting in an overabundant relic in the minimal setup. An additional neutrino-portal mediator can provide the required depletion while leaving the gamma-ray and antiproton signals essentially unchanged. We further show that paleo-detectors provide a powerful probe of the inelastic interpretation, requiring exposures of $\sim10$ and $\sim100$~mg Gyr for the endothermic and exothermic scenarios, respectively.
