Considerations on measuring spin-spin correlation of hyeprons in heavy-ion experiments

The significant global spin alignment observed for $\phi$ mesons in heavy-ion collisions has sparked intense discussions about its origin and implications. One explanation suggests that fluctuations in the strong force field may introduce strong spin correlations between strange ($s$) and anti-strange ($\bar{s}$) quarks, leading to the global spin alignment of $\phi$ mesons. Extending this line of research, the theoretical community has proposed studying the spin correlation between $\Lambda$ and $\bar{\Lambda}$ hyperons. In this paper, we construct experimental observables and make connections between them and the theoretical proposed quantities.