Search for supersymmetric partners of third generation quarks in leptonic channels with the ATLAS detector

TL;DR

This paper reports on ATLAS searches for supersymmetric partners of third-generation quarks, focusing on various mass spectra and models, using 36 fb$^{-1}$ of 13 TeV collision data, but finds no evidence of such particles.

Contribution

It extends previous searches to a broader range of mass splittings and models, including compressed spectra and R-parity violating scenarios.

Findings

No evidence for supersymmetric third-generation quark partners.

Constraints placed on masses and models of stop and sbottom.

Analysis covers diverse decay channels and mass configurations.

Abstract

Two of the most important parameters in supersymmetry are the masses of the stop and sbottom, the supersymmetric partners of the third generation quarks. A stop mass lighter than 1 TeV is favored theoretically, however, conventional searches based on the simplified models have not produced experimental evidence for a light stop. It is possible that the light stop evades our searches due to a compressed sparticle mass spectrum. Therefore, the searches are extended to cover a broader range of signal scenarios with different mass splittings between the stop, neutralino(s), and chargino(s). The searches are then interpreted in the context of both simplified models and pMSSM models. Searches are also performed for various R-parity violating stop (sbottom) models. Recent ATLAS results from searches for direct stop (sbottom) pair production are presented in final states with jets, missing transverse-momentum, and leptons. The analyses are based on 36 fb$^{-1}$ of $\sqrt{s}$=13 TeV proton-proton collision data recorded with ATLAS detector at the LHC in 2015 and 2016.