发表机构
Center for Theoretical Physics – a Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院莱因韦伯理论物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究将LZ实验观测到的248 keV核反冲事件解释为重higgsino暗物质，通过非弹性散射和参数拟合，确定质量约10^5-10^6 GeV，并借助早期物质主导时期的冻结机制解决产生问题。
AI 中文摘要
LZ实验最近报告了一个能量为248 keV的核反冲事件，该事件发生在预期背景较低的区域内。纯higgsino通过Z玻色子进行非弹性散射是对该事件的一个令人兴奋的可能解释，但在热冻结过程解释所有暗物质所需的质量m_χ = 1.1 TeV下，该模型预测在对应于E_R≳350 keV的空高能边带中会有多个事件，并且进一步被IceCube探测器对来自太阳的高能中微子的搜索所排除。我们将higgsino质量尺度和中性态质量劈裂m_χ和δ拟合到该事件和空边带上。我们还重新计算了作为m_χ函数的太阳俘获界限。仅LZ数据的最佳拟合在低质量m_χ ≈ (240, 450) GeV处，但被太阳俘获所排除。与事件、空边带和太阳俘获界限最一致的参数空间是m_χ ≈ (10^5, 10^6) GeV，δ ≈ (330, 480) keV，这在一定程度上依赖于暗物质晕模型。这样的higgsino必须通过不同于标准冻结过程的其他方式产生；这可以通过在早期物质主导时期发生冻结过程来实现，该时期以再加热宇宙至温度T_RH ≈ 1 TeV结束。我们给出了一个简单的概念验证模型，该模型通过Kim-Nilles机制实现这一点，因此与Higgsino质量尺度的起源相关联，并解决了强CP问题。
英文摘要
The LZ experiment has recently reported a $248$ keV nuclear recoil event in a region where backgrounds are expected to be low. A pure higgsino scattering inelastically through a $Z$-boson is an exciting possible interpretation of this event, but at the mass required for thermal freeze-out to account for all dark matter, $m_χ= 1.1$ TeV, it predicts several events in the empty high-energy sideband corresponding to $E_R\gtrsim350$ keV and is further excluded by searches for high energy neutrinos coming from the Sun by the IceCube detector. We fit the higgsino mass scale and neutral state mass splitting, $m_χ$ and $δ$, to the event and the empty sideband. We additionally recompute solar capture bounds as a function of $m_χ$. The LZ data alone are best fit at low mass, $m_χ\approx (240,\,450)$ GeV, but is excluded by solar capture. The parameter space most consistent with the event, the empty sideband and the solar capture bound is $m_χ\approx (10^5,\,10^6) $ GeV with $δ\approx (330,\,480)$ keV, with some dependence on DM halo modeling. Such a higgsino must be produced by some other method than standard freeze-out; this can be achieved by freezing-out during a period of early matter domination which ends by reheating the universe to temperature $T_{\rm RH}\approx 1$ TeV. We give a simple proof of concept model which does this via a Kim-Nilles mechanism and therefore connects to the origin of the Higgsino mass scale and solves the strong CP problem.
Comments5 pages, 2 figures
