Invariant-mass distributions (top panels) of $\xiczero\rightarrow\xim\pionp$ candidates and their charge conjugates reconstructed in the transverse-momentum intervals $3\pt12$ \gevc for 0--10\% centrality (left panel) and $4\pt12$ \gevc for 30--50\% centrality (right panel). The bottom panels display the distributions of the residuals obtained by subtracting the background evaluated with the fit function.