A search is presented for an extended Higgs sector with two new particles, X and ϕ, in the process X→ϕϕ→(γγ)(γγ). Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at s=13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 138 fb−1. No evidence of such resonances is seen. Upper limits are set on the production cross section for mX between 300 and 3000 GeV and mϕ/mX between 0.5% and 2.5%, representing the most sensitive search in this channel.
Hayrapetyan et al. (Thu,) studied this question.