"Figure 9b" of "Search for nonresonant pair production of Higgs bosons in the $b\bar{b}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s}= 13$ TeV with the ATLAS detector"

Distributions of the reconstructed m_HH in data (shown by the black points), the estimated background (shown by the yellow histograms) in the VBF signal region with |Δη_HH| > 1.5.
The hatching shows the total uncertainty of the background estimate.
The distribution of the expected background is obtained using the best-fit values of the nuisance parameters in the fit to the data with the background-only hypothesis.
Distributions for three choices of couplings are shown: the SM, κ_λ= 6, and κ_2V = 0 (with all other couplings set to their SM values in the last two models), scaled so as to be visible on the plot.
The lower panels show the ratio of the observed data yield to the predicted background in each bin.
Events in the overflow bins are counted in the yields of the final bins.
In the HEPData entry, the raw value per histogram bin is provided, while in the published paper the values in the histogram are scaled by the bin width.

VBF（Vector Boson Fusion）信号区（|Δη_HH| >1.5）内，数据中重建的m_HH分布（黑色点表示）与估计背景分布（黄色直方图表示）。阴影部分显示背景估计的总不确定性。预期背景分布是在仅背景假设下对数据拟合时，使用干扰参数（nuisance parameters）的最佳拟合值得到的。图中展示了三种耦合参数选择下的分布：标准模型（SM）、κ_λ=6和κ_2V=0（后两种模型中所有其他耦合参数均设为其SM值），为便于显示已对分布进行缩放。下方面板展示了每个bin中观测数据产额与预测背景的比值。在HEPData条目里，提供了每个直方图bin的原始值；而在已发表的论文中，直方图中的数值已按bin宽度进行缩放。