"Figure 17" of "Combination of ATLAS and CMS searches for Higgs boson pair production at $\sqrt{s} = 13$ TeV"

Expected and observed 95% CL upper limits on the signal strength of the VBF HH production $\mu_{HH}^{VBF}$, defined as the ratio of the measured VBF HH cross section to the corresponding SM prediction, for ATLAS, CMS, and the combination from both experiments.The limits are obtained by fixing the ggF signal strength to the SM ggF prediction $(\mu_{HH}^{ggF}=1)$. The expected limits assume the absence of the VBF HH signal.