First results on top-quarks from ATLAS

TL;DR

This paper reports initial results from the ATLAS experiment at the LHC, identifying top-quark pair candidate events using data-driven background estimation methods in 7 TeV proton-proton collisions.

Contribution

It presents the first top-quark candidate event selection and background studies using early LHC data with the ATLAS detector.

Findings

Candidate events show kinematic properties consistent with top pair production.

Background estimation techniques are effective for early data analysis.

Initial evidence supports top-quark production at the LHC.

Abstract

The search for first top-quark pair candidate events and the related background studies using data-driven techniques are reported for about 300 inverse nb of 7 TeV proton-proton collision data delivered by the Large Hadron Collider (LHC) and collected with the ATLAS detector. Selected events are characterized by the presence of high-pT isolated charged lepton(s), high jet multiplicity, jet(s) identified as originating from b-quark by a secondary vertex tagger algorithm, and missing transverse energy. They reveal kinematics properties consistent with top pair production.