Searches for vector-like quarks and $t\bar{t}$ resonances with the ATLAS detector

TL;DR

This paper reports on searches for vector-like quarks and top-antitop resonances using ATLAS data from 2012, finding no significant excess and setting limits on various models.

Contribution

It presents new search results for vector-like quarks and $t\bar{t}$ resonances with detailed limits in multiple models using 8 TeV data.

Findings

No significant excess observed above Standard Model expectations.

Upper limits set on vector-like quark masses and branching ratios.

Constraints placed on topcolor $Z'$ and Kaluza-Klein gluon models.

Abstract

Searches for vector-like quarks and $t\bar{t}$ resonances are performed with the ATLAS experiment at the Large Hadron Collider using an integrated luminosity of 14.3~fb$^{-1}$ of proton-proton collisions recorded in 2012 at a center-of-mass energy of $\sqrt{s} = $ 8~TeV. Several final states have been exploited to carry out these searches such as lepton plus jets and opposite and same-sign dilepton final states. No significant excess of events above the Standard Model expectation is observed, and upper limits at 95$\%$ CL are derived for vector-like quarks of various masses in a two-dimensional plane of branching ratios, and for $t\bar{t}$ resonances in two benchmark models, a topcolor leptophobic $Z'$ and a Kaluza-Klein gluon.