The BESIII Collaboration, led by the Institute of High Energy Physics of the Chinese Academy of Sciences, has achieved the world’s most precise measurement of the electric dipole moment (EDM) of the Lambda (Λ) hyperon using quantum-entangled Λ–anti-Λ pairs produced in J/ψ decays. The result improves the experimental sensitivity by about three orders of magnitude compared with the previous measurement, providing a new way to probe charge-parity (CP) violation in particles containing strange quarks.

The study is published in Science.

One of the most profound mysteries in modern physics is why the observable universe is dominated by matter rather than antimatter. Although the Standard Model has been remarkably successful in describing elementary particles and their interactions, its known sources of CP violation are insufficient to account for this cosmic imbalance. Searching for additional sources of CP violation is therefore an important path toward physics beyond the Standard Model.