论文标题
$^{214} $ pb的详细$β$频谱计算，用于新物理搜索的液体氙气
Detailed $β$ spectrum calculations of $^{214}$Pb for new physics searches in liquid Xenon
论文作者
论文摘要
我们对$^{214} $ pb $ \至$ $^{214} $ bi地面状态的计算和不确定性进行了批判性评估，这是基础状态$β$ decay，$β$ decay是液体Xenon暗物质探测器中的主要背景来源，低于1 KEV。我们考虑原子交换效应，核结构和辐射校正的贡献。对于每种情况，我们发现的变化比以前估计的不确定性大得多，并讨论了原始计算的缺点。具体而言，通过使用自搭配的狄拉克 - 哈特里 - 平台计算，我们发现原子交换效应相对于先前的交换计算，原子交换效应将预测的通量增加了$ 10（3）\％$。此外，使用壳模型计算核结构对形状因子的贡献，我们发现与允许的形状因子有很强的分歧，并讨论了几种不确定性来源。在1-200 KEV窗口中，预测的通量高达20美元$ \％$。最后，我们讨论了先前使用的QED辐射校正中的遗漏和探测器的效果，并在$ \ gtrsim 1 \％$ MEV $^{ - 1} $级别上找到斜率的小变化，高达$ 3 \％$的幅度，由于$ \ \ nmatcal {o}（zα^2，$^2 lind）和$ 3.的$ \ nightions $ \ s.^3 3^3^3^3^3^3^3^3）但不可用的高阶供款。结合在一起，它们引起了1-200 KEV窗口中不确定性的至少因子2的增加。我们对测量和相关过渡的可能实验方案发表评论。
We present a critical assessment of the calculation and uncertainty of the $^{214}$Pb $\to$ $^{214}$Bi ground state to ground state $β$ decay, the dominant source of background in liquid Xenon dark matter detectors, down to below 1 keV. We consider contributions from atomic exchange effects, nuclear structure and radiative corrections. For each of these, we find changes much larger than previously estimated uncertainties and discuss shortcomings of the original calculation. Specifically, through the use of a self-consistent Dirac-Hartree-Fock-Slater calculation, we find that the atomic exchange effect increases the predicted flux by $10(3)\%$ at 1 keV relative to previous exchange calculations. Further, using a shell model calculation of the nuclear structure contribution to the shape factor, we find a strong disagreement with the allowed shape factor and discuss several sources of uncertainty. In the 1-200 keV window, the predicted flux is up to 20$\%$ lower. Finally, we discuss omissions and detector effects in previously used QED radiative corrections, and find small changes in the slope at the $\gtrsim 1\%$ MeV$^{-1}$ level, up to $3\%$ in magnitude due to omissions in $\mathcal{O}(Zα^2, Z^2α^3)$ corrections and $3.5\%$ uncertainty from the neglect of as of yet unavailable higher-order contributions. Combined, these give rise to an increase of at least a factor 2 of the uncertainty in the 1-200 keV window. We comment on possible experimental schemes of measuring this and related transitions.
