Search for dark photons from Higgs boson decays via ZH production with a photon plus missing transverse momentum signature from pp collisions at s = 13 TeV with the ATLAS detector

This paper describes a search for dark photons (γd) in proton-proton collisions at s$$ \sqrt{s} $$ = 13 TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons (H → γγd) produced through the ZH production mode. The transverse mass of the system, made of