Left panel: invariant-mass distribution of opposite-sign pairs (black solid circle marker) and same-sign pairs (red solid square marker) in SE, and opposite-sign pairs (blue open square marker) in ME. Right panel: invariant-mass distribution of the $\Omega^0_{\rm c}$ candidates obtained by subtracting the opposite-sign charge e$\Omega$ pairs in ME from the opposite-sign charge pairs in SE (black solid circle marker), and e$\Omega$ opposite-sign charge pairs coming from $\Omega^0_{\rm c}$ decay from PYTHIA 8 (green open circle marker).