Search for 3rd generation superpartners with the ATLAS experiment

TL;DR

This paper reports on ATLAS searches for third-generation superpartners, specifically stops and sbottoms, using 13 TeV collision data, extending previous methods to cover more challenging scenarios with compressed mass spectra.

Contribution

It introduces extended search strategies for light stops and sbottoms in compressed spectra scenarios, interpreting results within simplified and pMSSM models.

Findings

No evidence of superpartners found in the analyzed data.

Limits set on stop and sbottom masses in various models.

Search sensitivity improved for compressed spectra scenarios.

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. Recent ATLAS results from searches for direct stop (sbottom) pair production are presented in final states with jets and 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.