Study of semi-boosted top quark reconstruction performance on the line shape of a $t\bar{t}$ resonance

TL;DR

This paper evaluates semi-boosted top quark reconstruction techniques in $t\bar{t}$ events at the LHC, demonstrating improved efficiency and analyzing the impact of unfolding procedures on signal significance.

Contribution

It introduces a detailed study of semi-boosted topologies for top quark reconstruction and assesses the effects of unfolding on signal detection at the LHC.

Findings

Increased efficiency in semi-boosted top quark reconstruction.

Correlation between detector and particle-level kinematic variables.

Slight degradation in signal significance after unfolding.

Abstract

We study the top quark pair events production in $pp$ collisions in the $\ell$+jets channel at the LHC energy of $\sqrt{s} = 14$ TeV for Standard Model as well as new physics processes. We explore the usage of semi-boosted topologies where the top quark decays into a boosted hadronic $W$-jet and an isolated $b$-jet and study their performance in the $t\bar{t}$ events kinematic reconstruction. An efficiency increase is observed and the correlation of selected kinematic variables between the detector and particle level is studied. Quality of the reconstructed mass line shape of a $Z'$ model with applications in current LHC experiments is evaluated. The results of the unfolding procedure for chosen spectra and an explicit proof of a slight degradation in the signal significance after the unfolding procedure are presented using the Fully Bayesian unfolding technique.