Precision Electron Capture Branching Ratio Measurements for Double Beta Decay with TITAN

被称为中微子的神秘亚原子粒子仍未被完全理解。最近在世界上最大的核物理实验室欧洲核子研究中心（位于日内瓦附近）进行的一项有争议的实验报告称，中微子的速度可能比光速还快，超过了自然界的宇宙速度极限。大质量中微子的特性是物理学中最令人困惑的问题之一。有可能观测到一种特殊的衰变，称为无中微子双β衰变（0nuß），这为科学家们提供了深入了解中微子神秘本质的机会。虽然这个衰变过程还没有被观察到，但世界各地的地下实验室正在进行许多低计数率的实验来解决这个问题。如果观测到0nuß衰变，就需要详细了解潜在的核结构，从而根据0nuß衰变的半衰期来确定中微子的质量。核跃迁是用一个特殊的术语来描述的，称为核矩阵元素（NME），这是理论上计算的。这些计算可以使用2nuß衰变模式进行测试。不仅可以从2nuß衰变中提取NME，而且可以从ß衰变中几个原子核的电子捕获（EC）衰变分支中推断出部分NME。

Mysterious subatomic particles known as neutrinos are still not fully understood. A recent and controversial experiment at the world's largest nuclear physics laboratory CERN (located near Geneve) has reported that neutrinos may travel faster than the speed of light, exceeding nature's cosmic speed limit. The character of massive neutrinos is one of the most puzzling questions in physics. The possibility of observing a special kind of decay, called neutrinoless double-beta decay (0nußß), offers scientists the chance to gain insight into the mysterious nature of neutrinos. Although this decay process has yet to be observed, many low-counting rates experiments are being conducted worldwide in underground laboratories to address this problem. If the 0nußß decay is observed, detailed knowledge of the underlying nuclear structure will be required to determine the mass of the neutrino from the half-life of the 0nußß decay. The nuclear transition is described by a special term called the nuclear matrix elements (NME), that is calculated theoretically. These calculations can be tested using the 2nußß decay mode. Not only can the NME be extracted from the 2nußß decay, but part of the NME can be inferred from the electron capture (EC) decay branches of the several nuclei in ßß decays.