论文标题
稀有$^{40} $ k衰减，对基本物理学和地球的衰减有影响
Rare $^{40}$K decay with implications for fundamental physics and geochronology
论文作者
论文摘要
Potassium-40是一种广泛的，自然存在的同位素，其放射性会影响亚原子的罕见事物搜索，核结构理论和估计的地质年龄。从未观察到直接直接至氩40基态的预测电子捕获衰减。 KDK（钾衰减）合作报告了这种罕见衰变模式的有力证据。一项盲目的分析揭示了地面电子捕获的强度（$ i _ {\ text {ec}^0} $）与激发态的（$ i_ \ text {ec*} $）$ i _ {\ i _ { \ stackrel {\ text {stat}} {\ pm} 0.0022 \ stackrel {\ text {sys}} {\ pm} {\ pm} 0.0010 $（68％c.l.），null假设拒绝为4 $σ$。就分支比率而言，该信号产生$ i _ {\ text {ec}^0} = 0.098 \％\ stackrel {\ text {stat}} {\ pm} 0.023 \％\％\ stackrel stackrel对于各种领域[L. Hariasz等人，同伴论文，doi：10.1103/physrevc.108.014327]。
Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts subatomic rare-event searches, nuclear structure theory, and estimated geological ages. A predicted electron-capture decay directly to the ground state of argon-40 has never been observed. The KDK (potassium decay) collaboration reports strong evidence of this rare decay mode. A blinded analysis reveals a non-zero ratio of intensities of ground-state electron-captures ($I_{\text{EC}^0}$) over excited-state ones ($I_\text{EC*}$) of $ I_{\text{EC}^0} / I_\text{EC*} = 0.0095 \stackrel{\text{stat}}{\pm} 0.0022 \stackrel{\text{sys}}{\pm} 0.0010 $ (68% C.L.), with the null hypothesis rejected at 4$σ$. In terms of branching ratio, this signal yields $I_{\text{EC}^0} = 0.098\% \stackrel{\text{stat}}{\pm} 0.023\% \stackrel{\text{sys}}{\pm} 0.010\% $, roughly half of the commonly used prediction, with consequences for various fields [L. Hariasz et al., companion paper, DOI: 10.1103/PhysRevC.108.014327].
