发表机构
KIAS; Harvard University（韩国高等科学研究院; 哈佛大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一个最小 Majorana 单态-双重态模型，通过混合抑制解释 LZ 248 keV 事件，并满足遗迹丰度与 IceCube 限制，同时给出规范起源与超对称嵌入。
AI 中文摘要
我们构建了一个最小 Majorana 单态-矢量类双重态模型，用以解释 LZ 实验在 248 keV 附近报告的单个核反冲类事件。在由反冲能量推断出的质量劈裂下，电弱强度的 $Z$ 玻色子跃迁预计会产生数千个事件；单态-双重态混合抑制了事件率，同时不改变反冲能谱。固定耦合的解释则要求极端晕尾中存在更大的质量劈裂，但太阳引力加速度会消除这种抑制，而更大的劈裂会将反冲能移向 LZ 实验空的高能边带。在我们的模型中，相同的混合抑制了太阳俘获和湮灭，而协同湮灭所需的小质量间隙削弱了希格斯介导的冷却，使得被俘获的暗物质群体能够保持延展且处于非平衡态。在施加遗迹丰度并将事件率归一化为一个事件后，留下了一个二维的质量劈裂参数空间。热化群体给出了保守的 IceCube 限制 $\delta=$300-301 keV；采用我们的非热冷却假设并在树级处理弹性散射时，标称限制为 $\delta=$331-341 keV，接近 730-733 GeV 的遗迹密度端点，该端点也受到反冲能谱的青睐。我们概述了规范 $U(1)_N$ 对称性作为宇称和质量劈裂的起源，以及一个候选的 $R$ 对称超对称嵌入方案。
英文摘要
We construct a minimal Majorana singlet-vector-like-doublet model for the single nuclear-recoil-like event reported by LZ near 248 keV. At the splitting inferred from the recoil energy, an electroweak-strength $Z$ transition predicts thousands of events; singlet-doublet mixing suppresses the rate without moving the recoil spectrum. Fixed-coupling interpretations instead require a larger splitting in the extreme halo tail, but solar gravitational acceleration removes this suppression, while the larger splitting shifts recoils toward LZ's empty high-energy sideband. In our model the same mixing suppresses solar capture and annihilation, while the small mass gap required for coannihilation weakens Higgs-mediated cooling, allowing the captured population to remain extended and out of equilibrium. Imposing the relic abundance and normalizing the rate to one event leaves a two-dimensional mass-splitting parameter space. A thermalized population gives the conservative IceCube limit $δ=$300-301 keV; with our nonthermal cooling ansatz and elastic scattering treated at tree level, the nominal limit is $δ=$331-341 keV near the 730-733 GeV relic-density endpoint, which is also favored by the recoil spectrum. We outline a gauged $U(1)_N$ origin for the parity and splitting and a candidate $R$-symmetric supersymmetric embedding.
Comments13 pages, 4 figures; analysis and references updated
