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, X. L. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. 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, T. T. 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. M. Chen, T. Chen, W. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. K. Chen, J. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, X. C. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, M. C. Du, S. X. Du, S. X. Du, X. L. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, J. Fang, S. S. Fang, W. X. Fang, Y. Q. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng, L. Feng, Q. X. Feng
A search for CP violation with an entangled system of Ξ^{-}Ξ[over ¯]^{+} pairs is performed, using (10,087±44)×10^{6} J/ψ events collected with the BESIII experiment. A nine-dimensional helicity amplitude is used to fit e^{+}e^{-}→J/ψ→Ξ^{-}Ξ[over ¯]^{+} and its subsequent decays. The Ξ^{-} and Ξ[over ¯]^{+} decay parameters are determined with higher precision compared to the best results reported so far. Furthermore, the strong phase difference, (δ_{P}-δ_{S})=(0.3±1.2±0.2)×10^{-2} rad, and the weak phase difference, (ξ_{P}-ξ_{S})=(-0.2±1.2±0.1)×10^{-2} rad, are directly determined. These are the most precise measurements to date. The CP asymmetry observables A_{CP}^{Ξ}=(-7.8±4.8±0.8)×10^{-3} and Δϕ_{CP}^{Ξ}=(0.6±5.1±0.2)×10^{-3} rad are determined, which are consistent with CP conservation. In addition, independent measurements of the Λ decay parameter and CP asymmetry A_{CP}^{Λ}=(-2.9±4.3±0.7)×10^{-3} are also obtained, which are in agreement with the previous measurements, but with much improved precision.