"Figure 2a" of "Search for heavy resonances decaying into two Higgs bosons in the $\mathrm{b\bar{b}}τ^+τ^-$ final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

Distribution of the invariant mass of the di-$\tau$ system, reconstructed with the FastMTT algorithm, after the full event selection in the $\tau_{\mathrm{h}}\tau_{\mathrm{h}}$ channel. The data (solid circles) are compared to the background simulation (filled histograms), where the gray bands represent the total background uncertainty, obtained from the post-fit values of the dominant systematic uncertainties and the statistical uncertainties in the simulated samples. The $X\to HH$ signal simulation (solid red line) is overlaid and normalized to $\sigma(X\to HH)=0.1~\mathrm{pb}$ for illustration. The ratio between the data and the total expected background contribution is shown in the lower panel, where a solid black triangle indicates those bins where the ratio exceeds the axis range.