  The first search for soft unclustered energy patterns (SUEPs) is performed
using an integrated luminosity of 138 fb$^{-1}$ of proton-proton collision data
at $\sqrt{s}$ = 13 TeV collected in 2016-2018 by the CMS detector at the LHC.
Such SUEPs are predicted by Hidden Valley models with a new, confining force
with a large 't Hooft coupling. In events with boosted topologies, selected by
high-threshold hadronic triggers, the multiplicity and sphericity of clustered
tracks are used to reject the background from standard model quantum
chromodynamics. With no observed excess of events over the standard model
expectation, limits are set on the cross section for production via gluon
fusion of a scalar mediator with SUEP-like decays.
