${[\alpha\mathrm {({{\mathit \Xi}^{-}})}\alpha_-({{\mathit \Lambda}}) − {{\overline{\mathit \alpha}}}{{{\overline{\mathit \Xi}}^{+}}}\alpha_+({{\overline{\mathit \Lambda}}})]\over [\alpha\mathrm {({{\mathit \Xi}^{-}})}\alpha_-({{\mathit \Lambda}}) + {{\overline{\mathit \alpha}}}{{{\overline{\mathit \Xi}}^{+}}}\alpha_+({{\overline{\mathit \Lambda}}})]}$
INSPIRE search
This is zero if $\mathit CP$ is conserved. The $\alpha $'s are the decay-asymmetry parameters for ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$ and ${{\mathit \Lambda}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{-}}$ and for ${{\overline{\mathit \Xi}}^{+}}$ $\rightarrow$ ${{\overline{\mathit \Lambda}}}{{\mathit \pi}^{+}}$ and ${{\overline{\mathit \Lambda}}}$ $\rightarrow$ ${{\overline{\mathit p}}}{{\mathit \pi}^{+}}$.
