A search is performed for a heavy scalar resonance X decaying to a Higgs boson (H) and a Higgs-like scalar boson (Y) in the two bottom quark (H bb) and four quark (Y VV 4q) final state, where V denotes a W or Z boson. Masses of the X between 900 and 4000 GeV and the Y between 60 and 2800 GeV are considered. The search is performed in data collected by the CMS experiment at the CERN LHC from proton-proton collisions at 13 TeV center-of-mass energy, with a data set corresponding to a total integrated luminosity of 138 fb^-1. It targets the Lorentz-boosted regime, in which the products of the H bb decay can be reconstructed as a single large-area jet, and those from the Y VV 4q decay as either one Y 4q or two V to qq jets. Jet identification and mass reconstruction exploit machine-learning tools, including a novel attention-based 'particle transformer' for Y 4q identification. No significant excess is observed in the data above the standard model background expectation. Upper limits on the product of production cross section and branching fraction as low as 0. 2 fb are derived at 95% confidence level for various mass hypotheses. This is the first search at the LHC for scalar resonances in the all-hadronic bbVV decay channel.
Hayrapetyan et al. (Thu,) studied this question.