Search for heavy resonances decaying into a photon and a hadronically decaying Higgs boson in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

TL;DR

This paper reports a search for new heavy resonances decaying into a Higgs boson and a photon in proton-proton collisions at 13 TeV, using ATLAS data, with no significant excess found and limits set on production cross-sections.

Contribution

It introduces a novel jet constituent analysis algorithm for identifying hadronically decaying Higgs bosons within large-radius jets in this search.

Findings

No significant excess observed above background.

Upper limits set on production cross-section times branching fraction.

Resonance mass range from 0.7 to 4 TeV excluded at 95% CL.

Abstract

This Letter presents a search for the production of new heavy resonances decaying into a Higgs boson and a photon using proton-proton collision data at $\sqrt{s}=13$ TeV collected by the ATLAS detector at the LHC. The data correspond to an integrated luminosity of 139 fb$^{-1}$. The analysis is performed by reconstructing hadronically decaying Higgs boson $(H\to b\bar{b})$ candidates as single large-radius jets. A novel algorithm using information about the jet constituents in the center-of-mass frame of the jet is implemented to identify the two $b$-quarks in the single jet. No significant excess of events is observed above the expected background. Upper limits are set on the production cross-section times branching fraction for narrow spin-1 resonances decaying into a Higgs boson and a photon in the resonance mass range from 0.7 to 4 TeV, cross-sections times branching fraction are excluded between 11.6 fb and 0.11 fb at a 95% confidence level.