Measurement of the Λ electric dipole moment with an entangled baryon-antibaryon system
- M. Ablikim
- M. N. Achasov
- P. Adlarson
- X. C. Ai
- R. Aliberti
- A. Amoroso
- Q. An
- Y. Bai
- O. Bakina
- Y. Ban
- H.-R. Bao
- S. S. Bao
- V. Batozskaya
- K. Begzsuren
- N. Berger
- M. Berlowski
- M. Bertani
- D. Bettoni
- F. Bianchi
- E. Bianco
- A. Bortone
- I. Boyko
- R. A. Briere
- A. Brueggemann
- H. Cai
- M. H. Cai
- X. Cai
- A. Calcaterra
- G. F. Cao
- N. Cao
- S. A. Cetin
- X. Y. Chai
- J. F. Chang
- G. R. Che
- Y. Z. Che
- C. H. Chen
- Chao Chen
- G. Chen
- H. S. Chen
- H. Y. Chen
- M. L. Chen
- S.-J. Chen
- S. L. Chen
- S. M. Chen
- T. Chen
- X. R. Chen
- X. T. Chen
- X. Y. Chen
- Y. B. Chen
- Y. Q. Chen
2026-09-03
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 Λ Λ ¯ 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.