论文标题
下一个实验对XE-124双电子捕获的敏感性
Sensitivity of the NEXT experiment to Xe-124 double electron capture
论文作者
论文摘要
富含质子的核的双电子捕获是类似于双β衰减的二阶核过程。尽管它们相似，但衰减签名却完全不同，有可能提供一个新的渠道来测量这些衰变的假设中性s模式。已经预测了许多同位素的标准模型允许的两种双电子捕获（$2νECEC$），但仅在$^{78} $ kr，$^{130} $ ba和最近，最近，$^{124} $ xe观察到。对这种衰减的敏感性为最终实验目标建立了基准，即也有可能发现该过程的Lepton-number-number-violation中微子版本，$0NνECEC$。在这里，我们报告了下一个白人检测器对$^{124} $ XE $2νECEC$的当前灵敏度，以及推断到Next-100。使用$^{124} $ XE耗尽的气体操作的$2νECEC$信号的仿真数据和来自Next-White的真实数据作为背景，我们定义了最佳的事件选择，从而最大程度地提高了下一个白色灵敏度。我们估计，对于下一个100，用Xenon气体运行，同位素富含1千克$^{124} $ XE，并且在5年的运行中，对$2νECEC$ 6年寿命的敏感性为$ 6 \ times $ 6 \ tims 10^{22} {22} $ y（以90％的置信度）或更高的能力可以达到。
Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture ($2νECEC$) has been predicted for a number of isotopes, but only observed in $^{78}$Kr, $^{130}$Ba and, recently, $^{124}$Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, $0νECEC$. Here we report on the current sensitivity of the NEXT-White detector to $^{124}$Xe $2νECEC$ and on the extrapolation to NEXT-100. Using simulated data for the $2νECEC$ signal and real data from NEXT-White operated with $^{124}$Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of $^{124}$Xe and for a 5-year run, a sensitivity to the $2νECEC$ half-life of $6 \times 10^{22}$ y (at 90% confidence level) or better can be reached.
