中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

This talk will present a search for Standard Model Higgs boson produced in association with high-energy photon via VBF production mode and another search for high mass resonance decaying to a Higgs boson and a photon with the ATLAS detector at $\sqrt{s}$=13 TeV. In both searches, the Higgs boson is required to decay to $b$-quark pairs. For the first search, $pp$ collision data with an integrated luminosity of 132 fb$^{-1}$ are used. A measured Higgs boson signal strength from these data is 1.3$\pm$1.0 corresponding to a 1.3$\sigma$ significance where the expected significance is 1.0. After combining with the search for Higgs boson decaying to $b$-quark pair via VBF production model without photon, the observed significance reaches above 3$\sigma$. Beside the search for non-resonance Higgs boson and photon production, this talk also reports the search result of high mass resonance decaying to a Higgs boson and an energetic photon which uses 139 fb$^{-1}$ $pp$ collision data. This search explores the resonance mass range of 600 GeV - 4 TeV, which results a boosted Higgs boson with two $b$-jets merged. The large-radius jet algorithm is used to reconstruct such Higgs boson and a novel Higgs boson tagging technique, Center-of-mass (CoM) tagger, is performed to improve the performance of identifying the $b$-quark pair decay of the Higgs boson. No significant derivation with respected to the Standard Model prediction is observed from data in the search region and model-independent cross section limits are derived for various resonance hypotheses.