"Auxiliary figure 4d" of "Search for light long-lived neutral particles from Higgs boson decays via vector-boson-fusion production from $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector"

Observed (solid line) and expected (dashed line) 95% CL upper limits on B(H→ 2γ_d+X) for FRVZ processes with a 125 GeV Higgs boson as a function of dark photon mean proper decay length for the ggF, WH and VBF analyses. The full combination is shown as solid or dashed black lines for a dark photon mass of 900 MeV.