Search for C P violations in the production and decay of hyperon-antihyperon pairs

This study introduces a complete joint angular distribution analysis for the process e + e − → J / ψ → B ( → B 1 π ) B ¯ ( → B ¯ 1 π ) with polarized beams, where B and B 1 are hyperons. We consider both transverse and longitudinal beam polarization and analyze C P violation in the production and decay of hyperons. We present the complete Fisher information matrix for the sensitivities of the weak decay parameters α − , α + , ϕ Ξ , and ϕ ¯ Ξ , the P -violating term F A , and the EDM d B (derived from the C P -violating term H T ), under the BESIII and STCF statistics. We find that polarization enhances the sensitivity of the parameters. Specifically, longitudinal polarization provides a more significant improvement compared to transverse polarization, with the enhancement being more pronounced for single-step decays than for multistep decays. With the expected statistics from the BESIII experiment, the estimated EDM sensitivities for Λ and Σ + are on the order of 10 − 19 e c m , while those for Ξ − and Ξ 0 are 10 − 18 e c m . The upcoming STCF experiment is expected to improve these estimates by 1–2 orders of magnitude. Furthermore, C P violation in hyperon decays originates from weak-phase differences among partial-wave amplitudes. Based on a refined isospin analysis, we emphasize the non-negligible contr