与LUX-ZEPLIN高能核反冲事件及IceCube约束相容的Higgsino暗物质

中文摘要 AI 辅助

我们研究了Higgsino暗物质（DM）作为LUX-ZEPLIN（LZ）实验报告的248 keV核反冲感兴趣事件的潜在解释，并考虑了IceCube对太阳中暗物质湮灭的约束。在近乎纯Higgsino极限下，两个由小质量劈裂δ分隔的中性Majorana态通过非对角耦合与Z玻色子相连，为无碰撞暗物质提供了自然实现。利用似然分析，我们确定了与LZ事件相容且与IceCube搜索零结果一致的90%置信区域，无论是否包含LZ高能边带无事件约束。在我们的LZ分析中，我们考虑了标准晕模型中暗物质分布，以及大麦哲伦云（LMC）引起的高速尾可能增强。我们给出了IceCube对Higgsino暗物质的四组边界变体，取决于对太阳中冷却通道的不同假设，这源于Higgsino-核子弹性散射（对直接探测不重要但对IceCube边界至关重要）的严重理论不确定性。当包含LMC引起的高速尾且忽略太阳中弹性冷却和LZ高能边带约束时，质量为1.1 TeV的热Higgsino仅勉强与LZ事件和IceCube限制相容；而更高质量的Higgsino则是LZ事件的优秀候选者，鉴于IceCube约束。根据晕分布、冷却相互作用以及是否包含LZ高能边带，Higgsino参数空间(m_χ, δ)中的相容区域从约2 TeV扩展到数百TeV或更高，质量劈裂范围约为350至525 keV。

英文摘要

We examine Higgsino dark matter (DM) as a potential explanation of the $248~\mathrm{keV}$ nuclear-recoil event of interest reported by the LUX-ZEPLIN (LZ) experiment, taking into account IceCube constraints on DM annihilation in the Sun. In the nearly pure Higgsino limit, two neutral Majorana states separated by a small mass splitting $δ$ are connected by an off-diagonal coupling to the $Z$ boson, providing a natural realization of inelastic DM. Using a likelihood analysis, we identify 90\% confidence regions compatible with the LZ event and consistent with the null results of IceCube searches, both with and without including a constraint from the absence of events in the LZ high-energy sideband. In our LZ analysis, we consider the DM distribution in the Standard Halo Model alone as well as possible enhancements of the high-speed tail induced by the Large Magellanic Cloud (LMC). We present four variants of bounds from IceCube on Higgsino dark matter, depending on various assumptions on cooling channels in the Sun, motivated by severe theoretical uncertainties about Higgsino-nucleon elastic scattering (unimportant for direct detection but crucial for IceCube bounds). Whereas the thermal Higgsino with a mass of $1.1~\mathrm{TeV}$ remains only marginally compatible with both the LZ event and the IceCube limits when the LMC-induced high-speed tail is included and both elastic cooling in the Sun and the LZ high-energy sideband constraint are neglected, higher mass Higgsinos are excellent candidates for the LZ event in light of IceCube constraints. Depending on the halo distribution, cooling interactions, and whether the LZ high-energy sideband is included, the compatible regions in the Higgsino parameter space $(m_χ,δ)$ extend from masses of $\sim2~\mathrm{TeV}$ to hundreds of TeV or higher, with mass splittings ranging approximately from $350$ to $525~\mathrm{keV}$.

发表机构

• Weinberg Institute for Theoretical Physics, Department of Physics, The University of Texas at Austin（德克萨斯大学奥斯汀分校魏因伯格理论物理研究所）
• The Oskar Klein Centre, Department of Physics, Stockholm University（斯德哥尔摩大学奥斯卡·克莱因中心）
• Nordita, Stockholm University and KTH Royal Institute of Technology（诺迪塔，斯德哥尔摩大学和瑞典皇家理工学院）

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15 pages, 2 figures