  A search for production of the supersymmetric partners of the top quark, top
squarks, is presented. The search is based on proton-proton collision events
containing multiple jets, no leptons, and large transverse momentum imbalance.
The data were collected with the CMS detector at the CERN LHC at a
center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of
137 fb$^{-1}$. The targeted signal production scenarios are direct and
gluino-mediated top squark production, including scenarios in which the top
squark and neutralino masses are nearly degenerate. The search utilizes novel
algorithms based on deep neural networks that identify hadronically decaying
top quarks and W bosons, which are expected in many of the targeted signal
models. No statistically significant excess of events is observed relative to
the expectation from the standard model, and limits on the top squark
production cross section are obtained in the context of simplified
supersymmetric models for various production and decay modes. Exclusion limits
as high as 1310 GeV are established at the 95% confidence level on the mass of
the top squark for direct top squark production models, and as high as 2260 GeV
on the mass of the gluino for gluino-mediated top squark production models.
These results represent a significant improvement over the results of previous
searches for supersymmetry by CMS in the same final state.
