Measurements of parity violation in atomic ytterbium

在电弱相互作用的研究中，原子宇称破坏实验（PV）是一个强有力的工具，提供了关于标准模型和低能核物理的宝贵信息。由于其强大的PV效应（迄今为止在任何原子系统中观察到的最大效应）和许多稳定同位素的可用性，镱（Yb）是此类研究的绝佳体系。这使得对一系列Yb同位素进行高精度测量成为可能，这将作为这些不同同位素之间中子表皮变化的探针，以及对标准模型之外的物理学的探针。此外，对Yb中PV效应的核自旋依赖贡献的确定将是对核拟极点矩的观察，并将获得与强子弱相互作用相关的核子-核子弱介子耦合的信息。我们最近完成了测量，首次观察到原子PV的同位素变化，我们已做好充分准备，以实现我们的Yb方案的主要科学目标：A。确定自旋对PV效应的贡献，并提取Yb核的核拟极点矩。这将通过精确测量自旋核同位素（171Yb, 173Yb）的超精细流形中PV效应的差异来实现。探索镱同位素链中中子表皮的变化以及标准模型之外的物理现象。这些目标将通过精确测量Yb同位素链中PV效应的比例来实现。

In the study of electro-weak interactions, atomic parity violation (PV) experiments form a powerful tool, providing valuable information about the Standard Model and low-energy nuclear physics. Ytterbium (Yb) is an excellent system for such studies, due to its strong PV effect (largest effect observed in any atomic system to date) and the availability of many stable isotopes. This brings within reach the possibility to perform high-precision measurements on a chain of Yb isotopes, which would serve as a probe of the neutron skin variation among these different isotopes, and a probe of physics beyond the Standard Model. In addition, a determination of the nuclear spin-dependent contributions to the PV effect in Yb would be an observation of the nuclear anapole moment, and would yield information about nucleon-nucleon weak meson couplings associated with hadronic weak interactions.Having recently completed measurements that resulted in the first observation of isotopic variation in atomic PV, we are fully prepared to tackle the main scientific objectives of our Yb programme:A. To determine the spin-dependent contributions to the PV effect and extract the nuclear anapole moment of the Yb nucleus. This will be achieved through precision measurements of the difference of the PV effect in the hyperfine manifold of the spinful nuclear isotopes (171Yb, 173Yb).B. To probe the variation of the neutron skin in a chain of Yb isotopes and physics beyond the Standard Model. These goals will be accomplished through precision measurements of the ratio of PV effects in a chain of Yb isotopes.