AI 中文总结
本研究探讨LZ实验的一个高能核反冲候选事件，提出费米型暗物质的氙核中性流吸收可解释该事件，但KamLAND数据的约束排除了该解释，存在显著张力并讨论了未来研究前景。
AI 中文摘要
LUX-ZEPLIN（LZ）实验在曝光量为2.80吨·年的条件下，于248±32.5 keV_nr的高能核反冲窗口报告了一个候选事件，而低能谱与本底预期一致。我们证明，该超出事例可由费米型暗物质在氙核上的中性流吸收自然解释：当暗物质质量m_χ≈247 MeV时，相干吸收过程产生248 keV_nr的单能核反冲；在该动量转移下，吸收过程进入非相干区域，与单个核子的散射产生从约200 keV到100.2 MeV的宽反冲谱。我们表明，单个有效场论耦合可同时在248±32.5 keV_nr窗口产生一个事件，且与相邻能区无事件观测的情况一致。所需的单核子吸收截面为σ_χN^NC=1.07×10^-46 cm²，对应有效场论标度Λ≈11.5 TeV。然而，对KamLAND关于中子发射道χ+¹²C→ν+n+¹¹C*的数据的重铸分析排除了该基准参数空间，确立了LZ超出事例解释与现有大体积闪烁体探测器约束之间的显著张力。我们讨论了该张力的含义及未来专用高能分析解决该问题的前景。
英文摘要
The LUX-ZEPLIN (LZ) experiment has reported a single candidate event in the high-energy nuclear recoil window $248\pm32.5\ \mathrm{keV}_{\mathrm{nr}}$ with an exposure of $2.84\ \mathrm{ton}\cdot\mathrm{yr}$, while the low-energy spectrum remains consistent with background expectations. We demonstrate that this excess can be naturally explained by the neutral-current absorption of fermionic dark matter on xenon nuclei. For a dark matter mass $m_χ\simeq 247\ \mathrm{MeV}$, the coherent absorption process produces a monoenergetic nuclear recoil at $E_R \simeq 248\ \mathrm{keV}_{\mathrm{nr}}$. At this momentum transfer, the absorption process enters the incoherent regime, where scattering off individual nucleons produces a broad recoil spectrum extending from $\sim 200\ \mathrm{keV}$ to $100.2\ \mathrm{MeV}$. We show that a single effective field theory coupling can simultaneously produce one event in the $248\pm32.5\ \mathrm{keV}_{\mathrm{nr}}$ window while remaining consistent with the non-observation of events in neighboring energy regions. The required single-nucleon absorption cross section is $σ_{χN}^{\mathrm{NC}} = 1.07\times10^{-46}\ \mathrm{cm}^2$, corresponding to an effective field theory scale $Λ\simeq 11.5\ \mathrm{TeV}$. However, a recasting analysis of KamLAND data on the neutron-emission channel $χ+{}^{12}\mathrm{C} \to ν+ n + {}^{11}\mathrm{C}^*$ excludes this benchmark parameter space, establishing a significant tension between the LZ excess interpretation and existing constraints from large-volume scintillator detectors. We discuss the implications of this tension and prospects for resolving it with future dedicated high-energy analyses.
Comments11 pages, 3 figures, 2 tables. Comments are welcome
