LZ事件的窄中微子窗口
A Narrow Neutrino Window for the LZ Event
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中文总结 AI 辅助
该研究提出一个框架，通过大气中微子在窄能量窗口内两步上升散射（ν→N1→N2）解释LZ实验的248 keV核反冲事件，并规避其他中微子实验的约束，利用暗物质背景参数共振和U(1)_B规范模型实现。主要贡献是提供一种中微子起源的机制，在LZ中产生O(1)事件。
中文摘要 AI 辅助
LUX-ZEPLIN (LZ) 实验报告了一个与248 keV核反冲一致的事件。解释较低能量反冲事件的缺失通常需要某种形式的上升散射，该散射在运动学上禁止此类事件。在这项工作中，我们提出了一个框架，其中LZ观测具有中微子起源，大气中微子在所需能量范围内提供主导通量。大气中微子上升散射到更重的中性态的情景也会在中微子实验中产生大量中性流事件。特别是，与氙相比，在较轻的核靶上散射会产生大得多的核反冲能量，然而尚未观察到此类超出。我们表明，如果大气中微子在一个窄能量窗口内首先产生一个近似单色的态N1，随后在LZ中N1上升散射到其更重的伙伴N2，则可以规避来自中微子实验的这一约束。在这种情景下，对于约250 MeV的N2质量，氙上的散射在运动学上变为允许，而在氧、碳以及大型中微子实验中使用的其他靶上的散射仍然在运动学上被禁止。我们表明，这一两步过程ν→N1→N2可以通过暗物质背景引起的参数共振来实现，该共振有效地产生N1，随后由具有规范U(1)_B的模型中矢量玻色子介导的N1→N2上升散射。后一种相互作用可以比弱相互作用强得多，这对于提升中微子底并产生LZ处的O(1)事件是必要的。
英文摘要
The LUX-ZEPLIN (LZ) experiment has reported an event consistent with a $248$ keV nuclear recoil. Explaining the absence of lower-energy recoil events typically calls for some form of upscattering that kinematically forbids such events. In this work, we present a framework in which the LZ observation has a neutrino origin, with atmospheric neutrinos providing the dominant flux in the required energy range. A scenario in which atmospheric neutrinos upscatter to a heavier neutral state would also produce a large number of neutral-current events in neutrino experiments. In particular, scattering on lighter nuclear targets results in much larger nuclear recoil energies compared to xenon, yet no such excess has been observed. We show that this constraint from neutrino experiments can be evaded if atmospheric neutrinos within a narrow energy window first produce a nearly monoenergetic state $N_1$, followed by the upscattering of $N_1$ to its heavier partner $N_2$ in LZ. In such a scenario, scattering on xenon becomes kinematically allowed for $N_2$ masses around $250$ MeV, while scattering on oxygen, carbon, and other targets used in large-scale neutrino experiments remains kinematically forbidden. We show that this two-step process, $ν\to N_1 \to N_2$, can be realized through a parametric resonance induced by a dark matter background that efficiently produces $N_1$, followed by $N_1 \to N_2$ upscattering mediated by a vector boson in a model with gauged $U(1)_B$. The latter interaction can be sufficiently stronger than the weak interaction, which is necessary to lift the neutrino floor and yield $\mathscr{O}(1)$ event at LZ.
发表机构
- Oklahoma State University（俄克拉荷马州立大学）
机构由 AI 辅助整理，请以论文原文为准。
