"Figure 1a" of "Search for low-mass vector and scalar resonances decaying into a quark-antiquark pair in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

The jet $m_{SD}$ distributions in the low-$p_{b\bar{b}}$ SR, fitted with the background-only hypothesis. The distributions are summed across all five $p_{T}$ bins and the four data-taking periods. The steplike features are due to the $\rho$ requirement, which results in a different $m_{\text{SD}}$ range for each $p_{T}$ bin. The hatched area shows the expected $Z'$ signal yields for $g_q=0.25$. The lower panel shows the residual difference between the data and the overall background, divided by the statistical uncertainty of the data; the gray band represents the systematic uncertainty in the background estimation.