2026-09-04 中国科学院（CAS）
Artistic illustration of the quantum-entangled Lambda–anti-Lambda system used in the BESIII electric dipole moment measurement. (Image by the BESIII Collaboration)
＜関連情報＞
- https://english.cas.cn/newsroom/research-news/202608/t20260831_1189514.shtml
- https://www.science.org/doi/10.1126/science.adx7334
エンタングルしたバリオン・反バリオン系を用いたΛ電気双極子モーメントの測定 Measurement of the Λ electric dipole moment with an entangled baryon-antibaryon system
BESIII Collaboration
Science Published:3 Sep 2026
DOI:https://doi.org/10.1126/science.adx7334
Abstract
The dominance of matter over antimatter in the Universe has consistently driven the pursuit of new physics beyond the Standard Model that violates charge-parity symmetry. Strange baryons (hyperons) remain a largely unexplored territory in which interactions between hyperons and particles from new physics could induce a nontrivial electric dipole moment (EDM). However, direct measurements of hyperon EDMs through spin precession are highly challenging owing to their short lifetimes. In this work, we introduce a method to extract the EDM of the lightest hyperon, Λ, using the entangled ΛΛ– system. Our result is consistent with zero, achieving a three-orders-of-magnitude improvement over the previous upper limit established in the 1980s with comparable statistics, providing stringent constraints on potential new physics.
