Search for top squark production in fully-hadronic final states in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports a search for top squark production in fully-hadronic final states using 13 TeV proton-proton collision data, employing deep neural networks for event classification, and sets new exclusion limits on top squark and gluino masses.

Contribution

The study introduces novel deep neural network algorithms to identify hadronically decaying top quarks and W bosons in supersymmetry searches, improving sensitivity over previous methods.

Findings

No significant excess observed over standard model predictions.

Exclusion limits up to 1310 GeV for top squark mass.

Exclusion limits up to 2260 GeV for gluino mass.

Abstract

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.