Towards a Microscopic and Precision Description of Nuclear Schiff Moments

by Prof. Jiangming Yao (Sun Yat-sen University)

Thursday 21 May 2026, 13:00 → 15:00 Asia/Tokyo

RIBF Hall, RIBF 2nd Floor (Wako)

Charge-parity (CP) violation is a key ingredient in explaining the matter-antimatter asymmetry of the Universe. However, the amount of CP violation predicted by the Standard Model is far too small to account for the observed baryon asymmetry, pointing to the existence of new CP-violating mechanisms beyond the Standard Model. A permanent electric dipole moment (EDM) of an elementary or composite system—such as a neutron, nucleus, atom, or molecule—would provide a sensitive and direct signal of such new physics. Consequently, the search for EDMs has become a major frontier in particle, nuclear, and atomic physics.

Among these efforts, measurements of atomic EDMs in diamagnetic atoms are of particular interest, since they are primarily induced by nuclear Schiff moments. The latter depend sensitively on nuclear structure and arise from parity- and time-reversal-violating (P, T-violating) nucleon-nucleon interactions. Atomic EDM experiments therefore provide a powerful probe of the low-energy constants that characterize P, T-violating nuclear forces. To connect such measurements to underlying sources of CP violation, reliable calculations of nuclear Schiff moments are indispensable. At present, however, theoretical predictions still suffer from an uncertainty of more than an order of magnitude.

In this talk, I will present a beyond-mean-field study of nuclear Schiff moments in experimentally relevant diamagnetic atoms based on state-of-the-art multireference covariant density functional theory. The results highlight the important roles of shape-mixing effects in determining nuclear Schiff moments. Finally, I will discuss preliminary results from ongoing ab initio studies of nuclear Schiff moments based on nuclear forces derived from chiral effective field theory.