发表机构
Department of Physics, Indian Institute of Science Education and Research - Bhopal（印度科学教育研究学院博帕尔分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出用大气中微子上散射产生超出标准模型粒子的机制，解释LZ实验观测到的248±23±23 keV孤立核反冲事件，确定了符合约束的参数空间。
AI 中文摘要
LUX-ZEPLIN（LZ）实验近期观测到一个能量为 $248\pm 23\pm 23$ keV 的孤立核反冲事件，由于标准模型背景估计无法解释该事件，促使学界寻找新物理层面的解释。目前多数已有文献考虑的是具有较重伙伴的银晕暗物质，而本研究采用大气中微子（$\nu$）上散射的替代路径，产生超出标准模型（BSM）的大质量粒子 $\chi$。此类散射的运动学要求在反冲能量下限处设置了截断，从而可解释该高反冲能量处的独特孤立事件。这种中微子与核子（$\nuc$）的上散射过程 $\nu \nuc\to \chi \nuc$ 可自然在惰性中微子模型中实现，不过本研究的分析是通用的，未对 $\chi$ 做具体限定。研究确定了能产生此类孤立事件的参数空间区域，假设存在质量为 $m_\phi$、耦合为 $y_{\chi,q}$ 的标量媒介子，例如当 $m_\chi\sim1$ GeV，且 $\sqrt{y_\chi y_q}/m_\phi=2 \times 10^{-2}$ GeV$^{-1}$ 时，可满足该事件过量的情况，同时也符合其他现有约束条件。
英文摘要
The recent observation of an isolated nuclear recoil at $248\pm 23\pm 23$ keV energy by LUX-ZEPLIN (LZ) experiment has motivated the community to look for a new physics explanation, as the Standard model background estimation fails to accomodate that. Most of the existing literature hitherto considers a galactic halo dark matter with a heavier partner. In this work, we traverse the alternate route of atmospheric neutrino ($ν$) up-scattering, thus producing a massive beyond standard model (BSM) particle $χ$. The kinematic requirement of such a scattering poses a cut off in the lower recoil energies providing an explanation of the unique isolated event at such a higher recoil energy. Such up-scattering with the nucleons ($\nuc$), $ν\nuc\to χ\nuc$ can be naturally realized in sterile neutrino models, though we keep our analysis generic without specifying $χ$. We identify the region of parameter space that can produce such an isolated event assuming a scalar mediator with mass $m_ϕ$ and coupling $y_{χ,q}$. For example, with $m_χ\sim1$ GeV, and $\sqrt{y_χy_q}/m_ϕ=2 \times 10^{-2}$ GeV$^{-1}$ can satisfy such an excess of events while remaining allowed by other existing constraints as well.
Comments4 pages, 2figures
