Measurement of the inclusive $t\bar{t}$ cross-section in the lepton+jets channel in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

Abstract

The inclusive $t\bar{t}$ production cross-section is measured in the lepton+jets channel using 20.2 fb${}^{-1}$ of proton--proton collision data at a centre-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. Major systematic uncertainties due to the modelling of the jet energy scale and $b$-tagging efficiency are constrained by separating selected events into three disjoint regions. In order to reduce systematic uncertainties in the most important background, the W+jets process is modelled using Z+jets events in a data-based approach. The inclusive $t\bar{t}$ cross-section is measured with a precision of 5.7% to be ${\sigma }_{t\bar{t}}=248.3\pm 0.7(stat.)\pm 13.4(syst.)\pm 4.7(lumi.)\text{pb}$, assuming a top-quark mass of 172.5 GeV. The result is in agreement with the Standard Model prediction.

5 pages, 2 figures, conference: 10th International Workshop on Top Quark Physics, Braga, Portugal, 17 - 22 Sep 2017