Gluon-Photon Signatures for color octet at the LHC (and beyond)

Abstract

We consider a color octet scalar particle and its exotic decay in the channel gluon-$\gamma$ using an effective Lagrangian description for its strong and electromagnetic interactions. Such a state is present in many extensions of the Standard Model, and in particular in composite Higgs models with top partial compositeness, where couplings to photons arise via the Wess-Zumino-Witten term. We find that final states with one or two photons allow for a better reach at the LHC, even for small branching ratios. Masses up to $1.2$ TeV can be probed at the HL-LHC by use of all final states. Finally, we estimate the sensitivity of the hadronic FCC.

Comments: 26 pages, 13 figures, 7 tables, 2 appendices; v2: Discussion in Sec. 2.2 extended, table 2 added, typos fixed, version published in JHEP