We study associated production of the Higgs boson with a photon in various extended Higgs models at future electron-positron colliders. The process is loop-induced, and hence the cross sections are sensitive to additional scalars and model parameters. We discuss how much new physics contributions can enhance the signal rate.
The talk is based on [S.Kanemura, K.Mawatari, K.Sakurai, Phys. Rev. D99 (2019) 035023 (arXiv:1808.10268)].