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: SAPPJ-2015-00027
• 负责人: Gwinner, Gerald
• 金额: $ 11.66万
• 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: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=591552
• 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 non-conservation: 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 non-conservation 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 are slowed down with laser light and captured into a magneto-optic laser trap, suspended in free space at temperatures millions of times colder than room temperature. Together with researchers from the United States and Mexico, including 3 PhD students, one postdoctoral fellow, and several undergraduate research students, we have established a francium trapping facility at ISAC and have carried out first measurements with trapped Fr atoms, concerning the distribution of magnetization inside the nucleus in a string of isotopes. In a next step, we are now setting up experiments using precise laser and microwave spectroscopy to ultimately study atomic parity non-conservation in francium. The microwave experiment will measure a parity non-conserving effect inside the nucleus known as the anapole moment. 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 non-conservation in nuclear matter. The laser experiment will search for 'new' physics outside the - so far very successful - Standard Model of particle physics by measuring nuclear-spin independent atomic parity non-conservation in francium.

自然界的基本力量是可以在triumf的加拿大放射性横梁设施ISAC研究的引人入胜的主题之一。特别是，造成核的β-末期的弱力在表现出奇偶校验的现象中是独一无二的：在自然界中未观察到由弱力介导的物理过程的镜像。 ISAC提供了研究原子奇偶校验在Francium（FR）中的独特可能性，该元素将非常沉重的核（Z = 87）与碱的简单，基本类似氢的价值结构结合在一起。 FR核是周期表中前103个元素中最不稳定的核，这是寿命最长的同位素衰变，仅在23分钟内。为了获得微小样品的最佳使用，将FR原子用激光光降低，并将其捕获到磁极的激光陷阱中，在温度下悬浮在自由空间中，比室温冷数百万倍。我们与来自美国和墨西哥的研究人员，包括3名博士学位学生，一名博士后研究员以及几位本科研究生，我们在ISAC建立了一家法兰西捕获设施，并通过捕获的FROM进行了首先测量，涉及磁线分布在原子核内部的同位素。下一步，我们现在正在使用精确的激光和微波光谱进行实验，以最终研究Francium中的原子均衡性不保守。微波实验将测量被称为Anapole矩的细胞核内的平均值非连接效应。迄今为止，仅进行了两个单一同位素和tallium的同位素的测量，并且更多的数据对于更好地理解核物质中的Hadronic奇偶校验至关重要。激光实验将通过测量法兰克（Francium）的核旋转独立原子奇偶校验不保守来搜索 - 到目前为止非常成功的粒子物理标准模型的“新”物理学。