ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

TL;DR

This paper reports on ATLAS Run 1 searches for direct pair production of third-generation squarks, setting exclusion limits in supersymmetric models due to no observed evidence of these particles.

Contribution

It introduces new analyses to enhance sensitivity and combines multiple analyses to set comprehensive exclusion limits on third-generation squarks.

Findings

No evidence of third-generation squarks was observed.

Exclusion limits were established in simplified and phenomenological SUSY models.

Enhanced analysis techniques improved sensitivity to specific parameter regions.

Abstract

This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 fb$^{-1}$ of collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV, although in some case an additional 4.7 fb$^{-1}$ of collision data at $\sqrt{s}$ = 7 TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space. Since no evidence of third-generation squarks is found, exclusion limits are derived by combining several analyses and are presented in both a simplified model framework, assuming simple decay chains, as well as within the context of more elaborate phenomenological supersymmetric models.