(Upper panels) invariant mass distributions of $\Lambda$ (left) and $\overline\Lambda$ (right) candidates for 20$-$30% centrality range in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV using data collected during the LHC operation in 2011. Dashed lines show the result of the fit for $N_{\rm BG}(M_{\rm inv})$ in Eq. (10). (Bottom panels) Global polarization extraction via fit to $\langle \mathrm{sin}(\phi_{\rm p}^* - \Psi_{\rm SP})\rangle$ as a function of the invariant mass, with $\Psi_{\rm SP}$ reconstructed with the ZDC on the target ($\eta < 0$ side). Dashed and solid lines show $L_{\rm BG}(M_{\rm inv})$ and the combined fit with Eq. (9). See text for more details.