Fundamental symmetry tests with the francium laser trap facility at ISAC

使用 ISAC 的钫激光陷阱设施进行基本对称性测试

• 批准号: 372476-2012
• 负责人: Gwinner, Gerald
• 金额: $ 10.56万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=550179
• 关键词: Fundamental; symmetry; tests; francium; laser

The fundamental forces of nature are one of the fascinating subjects that can be studied at ISAC, Canada's radioactive beam facility at TRIUMF. In particular, the weak force, causing the beta-decay of nuclei, is unique in exhibiting the phenomenon of parity-violation: the mirror images of physical processes mediated by the weak force are not observed in nature. ISAC offers a unique possibility to study atomic parity-violation in francium (Fr), an element combining a very heavy nucleus (Z=87) with the simple, essentially hydrogenlike, valence structure of an alkali. Fr nuclei are the least stable among the first 103 elements in the periodic table, the longest-lived isotope decays in only 23 minutes. To make optimum use of the minute sample, the Fr atoms will be slowed down with laser light and captured into a `magneto-optical' laser trap, suspended in free space at temperatures millions of times colder than room temperature. We have established a francium trapping facility at ISAC; in collaboration with researchers from the United States and Mexico, we will then use this francium source to carry out a series precision experiments using laser and microwave spectroscopy. First we will measure what is known as the hyperfine anomaly in a string of francium isotopes, giving us insight into the distribution of the nuclear magnetic moment within the nucleus. Another goal is to study parity-violating nucleon-nucleon interactions in francium by observing the nuclear anapole moments in a chain of francium isotopes; to date, only measurements in two single isotopes of cesium and thallium have been performed, and more data is crucial for a better understanding of hadronic parity violation in nuclear matter. Ultimately, we want to search for `new' physics outside the - so far very successful - Standard Model of particle physics by measuring nuclear-spin independent atomic parity-violation in francium.

自然的基本力量是一个迷人的主题，可以在ISAC，加拿大的放射性束设施在TRIUMF研究。特别是，导致原子核β衰变的弱力在显示宇称破坏现象方面是独一无二的：由弱力介导的物理过程的镜像在自然界中是观察不到的。ISAC提供了一个独特的可能性，研究原子宇称违反在<$（Fr），一个元素结合了一个非常重的核（Z=87）与简单的，基本上是氢，价结构的碱金属。在元素周期表的前103种元素中，Fr核是最不稳定的，寿命最长的同位素衰变仅需23分钟。为了最大限度地利用微小的样品，Fr原子将被激光减速，并被捕获到一个“磁光”激光陷阱中，悬浮在自由空间中，温度比室温低数百万倍。我们已经在ISAC建立了一个<$捕获设施;与美国和墨西哥的研究人员合作，我们将利用这个<$源，利用激光和微波光谱学进行一系列精确的实验。首先，我们将测量在一系列的<$同位素中所谓的超精细异常，让我们了解原子核内的核磁矩分布。另一个目标是通过观察一系列的<$同位素中的核再极点矩来研究<$中宇称破坏的核子-核子相互作用;到目前为止，只有铯和铊的两个单一同位素进行了测量，更多的数据对于更好地理解核物质中的强子宇称破坏至关重要。最终，我们希望通过测量不依赖于核自旋的原子宇称违反，在粒子物理学的标准模型（迄今为止非常成功）之外寻找“新”物理学。