Measurements of parity violation in atomic ytterbium

• Applicant: Professor Dmitry Budker, Ph.D.
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 423116110

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.

• DFG Programme: Research Grants