Measurement of the top quark mass in the $t\bar{t}\to$ lepton+jets channel from $\sqrt{s}=8$ TeV ATLAS data and combination with previous results

TL;DR

This paper measures the top quark mass using ATLAS data at 8 TeV with a template method, achieving high precision and combining results with previous measurements for an improved estimate.

Contribution

It introduces a three-dimensional template technique to simultaneously determine the top quark mass and jet energy scale factors, enhancing measurement accuracy.

Findings

Top quark mass measured as 172.08 GeV with uncertainties

Combined top quark mass from multiple measurements is 172.69 GeV

Method improves precision of top quark mass determination

Abstract

The top quark mass is measured using a template method in the $t\bar{t}\to$ lepton+jets channel (lepton is $e$ or $\mu$) using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of $\sqrt{s}=8$ TeV and correspond to an integrated luminosity of 20.2 fb$^{-1}$. The $t\bar{t}\to$ lepton+jets channel is characterized by the presence of a charged lepton, a neutrino and four jets, two of which originate from bottom quarks ($b$). Exploiting a three-dimensional template technique, the top quark mass is determined together with a global jet energy scale factor and a relative $b$-to-light-jet energy scale factor. The mass of the top quark is measured to be $m_{top}= 172.08 \pm 0.39 (stat) \pm 0.82 (syst)$ GeV. A combination with previous ATLAS $m_{top}$ measurements gives $m_{top}= 172.69 \pm 0.25 (stat) \pm 0.41 (syst)$ GeV.