A Search for $t\bar{t}$ Resonances in Lepton Plus Jets Events with ATLAS using 14 fb$^{-1}$ of Proton-Proton Collisions at $\sqrt{s}$ = 8 TeV

TL;DR

This paper reports a search for new particles decaying into top-antitop pairs in proton-proton collisions at 8 TeV, setting limits on specific theoretical models using ATLAS data.

Contribution

It introduces a comprehensive search strategy for top-antitop resonances, including merged jet analysis, and sets new exclusion limits on certain BSM particles.

Findings

Excluded Z' bosons below certain mass thresholds

Excluded Kaluza-Klein gluons below certain mass thresholds

Demonstrated effectiveness of jet merging techniques in resonance searches

Abstract

Some Beyond the Standard Model theories predict new particles that decay predominantly into top-antitop quark pairs. A search for top-antitop quark resonances that decay into the lepton plus jets final state is carried out with the ATLAS experiment at the LHC using 14 fb$^{-1}$ of $\sqrt{s}$ = 8 TeV proton-proton collisions. The search considers both cases where all of the final state jets are isolated and where some or all of the top quark decay products are merged into a single jet. Mass exclusion limits at a 95% credibility level are set for two benchmark models, one predicting leptophobic topcolor Z' bosons and the other predicting Randall-Sundrum Kaluza-Klein gluons.