Measurement of the top quark pair production cross-section with ATLAS in the single lepton channel

TL;DR

This paper reports the measurement of top quark pair production cross-sections at 7 TeV using ATLAS data, employing two multivariate analysis methods in the single lepton channel, with results consistent with QCD predictions.

Contribution

It introduces two multivariate analysis techniques, including one with b-jet identification, to measure the top pair production cross-section in the single lepton channel at the LHC.

Findings

Measured cross-section: 187 +/- 11 (stat.) +18-17 (syst.) +/- 6 (lumi.) pb

Measured cross-section: 173 +/- 17 (stat.) +18-16 (syst.) +/- 6 (lumi.) pb

Results agree with QCD calculations

Abstract

A measurement of the production cross-section for top quark pairs (t tbar) in pp collisions at sqrt{s} = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in the single lepton topology by requiring an electron or muon, large missing transverse momentum and at least three jets. With a data sample of 35/pb, two different multivariate methods, one of which uses b-quark jet identification while the other does not, use kinematic variables to obtain cross-section measurements of sigma (t tbar) = 187 +/- 11 (stat.) +18-17 (syst.) +/- 6 (lumi.) pb and sigma (t tbar) = 173 +/- 17 (stat.) +18-16 (syst.) +/- 6 (lumi.) pb} respectively. The two measurements are in agreement with each other and with QCD calculations. The first measurement has a better a priori sensitivity and constitutes the main result of this Letter.