Measurement of the inclusive $t\bar{t}$ production cross section in the lepton+jets channel in $pp$ collisions at $\sqrt{s}$= 7 TeV with the ATLAS detector using support vector machines

Abstract

A measurement of the top quark pair-production cross section in the lepton+jets decay channel is presented. It is based on 4.6 fb$^{-1}$ of $\sqrt{s} = 7$ TeV $pp $ collision data collected during 2011 by the ATLAS experiment at the CERN Large Hadron Collider. A three-class, multidimensional event classifier based on support vector machines is used to differentiate $t\bar{t}$ events from backgrounds. The $t\bar{t}$ production cross section is found to be $\sigma_{t\bar{t}}=168.5 \pm 0.7$(stat.)$^{+6.2}_{-5.9}$(syst.)$^{+3.4}_{-3.2}$(lumi.) pb. The result is consistent with the Standard Model prediction based on QCD calculations at next-to-next-to-leading order.