A search is reported for pairs of light Higgs
bosons (H1) produced in supersymmetric cascade decays in
final states with small missing transverse momentum. A data
set of LHC pp collisions collected with the CMS detector
at √s = 13 TeV and corresponding to an integrated luminosity of 138 fb−1 is used. The search targets events where
both H1 bosons decay into bb pairs that are reconstructed ¯
as large-radius jets using substructure techniques. No evidence is found for an excess of events beyond the background expectations of the standard model (SM). Results
from the search are interpreted in the next-to-minimal supersymmetric extension of the SM, where a “singlino” of small
mass leads to squark and gluino cascade decays that can predominantly end in a highly Lorentz-boosted singlet-like H1
and a singlino-like neutralino of small transverse momentum.
Upper limits are set on the product of the squark or gluino pair
production cross section and the square of the bb branching ¯
fraction of the H1 in a benchmark model containing almost
mass-degenerate gluinos and light-flavour squarks. Under the
assumption of an SM-like H1 → bb branching fraction, H ¯ 1
bosons with masses in the range 40–120 GeV arising from the
decays of squarks or gluinos with a mass of 1200–2500 GeV
are excluded at 95% confidence level.