We search for new massive scalar particles X and Y through the resonant process X → YH → bbb¯ b, ¯ where
H is the standard model Higgs boson. Data from CERN LHC proton-proton collisions are used, collected
at a centre-of-mass energy of 13 TeV in 2016–2018 and corresponding to an integrated luminosity of
138 fb−1. The search is performed in mass ranges of 0.9–4 TeV for X and 60–600 GeV for Y, where both
Y and H are reconstructed as Lorentz-boosted single large-area jets. The results are interpreted in the
context of the next-to-minimal supersymmetric standard model and also in an extension of the standard
model with two additional singlet scalar fields. The 95% confidence level upper limits for the production
cross section vary between 0.1 and 150 fb depending on the X and Y masses, and represent a significant
improvement over results from previous searches.