Identification of high transverse momentum top quarks in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

TL;DR

This paper evaluates jet-substructure techniques for identifying high transverse momentum top quarks in proton-proton collisions at 8 TeV, demonstrating their effectiveness and introducing a new reconstruction method for complex events.

Contribution

The study assesses the performance of existing top quark identification methods and introduces a novel technique optimized for multi-jet events.

Findings

Monte Carlo simulations accurately predict performance.

Jet-substructure techniques achieve high signal efficiency.

New method improves top quark reconstruction in complex events.

Abstract

This paper presents studies of the performance of several jet-substructure techniques, which are used to identify hadronically decaying top quarks with high transverse momentum contained in large-radius jets. The efficiency of identifying top quarks is measured using a sample of top-quark pairs and the rate of wrongly identifying jets from other quarks or gluons as top quarks is measured using multijet events collected with the ATLAS experiment in 20.3 fb$^{-1}$ of 8 TeV proton-proton collisions at the Large Hadron Collider. Predictions from Monte Carlo simulations are found to provide an accurate description of the performance. The techniques are compared in terms of signal efficiency and background rejection using simulations, covering a larger range in jet transverse momenta than accessible in the dataset. Additionally, a novel technique is developed that is optimized to reconstruct top quarks in events with many jets.