Year: 2026
Type: preprint
Abstract: Searches for permanent electric dipole moments (EDMs) probe new sources of CP violation beyond the Standard Model. The atomic EDM of $^{171}\text{Yb}$, which is sensitive to its nuclear Schiff moment, is a promising candidate, but previous measurements were limited by noise and systematic effects induced by the optical dipole trap (ODT) that holds the atoms. Here we report a substantially improved search enabled by a dual-ODT configuration with orthogonal polarizations, and spin measurements for precise alignment of static and optical fields. By suppressing the key parity-mixing systematic effect and vector light-shift noise, we achieve a limit of $|d(^{171}\mathrm{Yb})| < 7.5 \times 10^{-28}\ e\cdot\text{cm}$ (95\% C.L.), which represents a 20-fold improvement over the previous work. We also present the first calculation of the nuclear structure factors of the Schiff moment of $^{171}\text{Yb}$. The experimental and theoretical advances combine to tighten constraints on CP-violating pion-nucleon couplings in a global analysis. Moreover, this work demonstrates a pathway toward future measurements in $^{225}\text{Ra}$, where nuclear deformation offers exceptional sensitivity to physics beyond the Standard Model.
Source: arXiv (Cornell University)
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222968690