Measurement of Single-top Quark Production with ATLAS Data

TL;DR

This paper reports on measurements of single-top quark production modes at the LHC using ATLAS data, providing cross-section results and limits that test the Standard Model and probe for new physics.

Contribution

First measurement of single-top production cross-sections at 7 TeV with ATLAS, including t-channel, s-channel, and Wt modes, using cut-based and neural network analyses.

Findings

Measured t-channel cross-section: 90 +32 -22 pb

Set upper limits for Wt and s-channel production

Results are consistent with Standard Model predictions

Abstract

Single-top production processes have been studied using 0.7 fb-1 of data from 7 TeV center-of-mass energy proton-proton collisions collected with the ATLAS detector at the LHC. Single-top is electroweak top production and the standard model includes three production modes. Each contains a Wtb vertex, allowing the possibility of a direct measurement of the CKM matrix element |Vtb|. Single-top could also be sensitive to new physics, such as flavor changing neutral currents or heavy W' bosons. Using cut-based selections, a limit of < 39.1 pb is set for dilepton Wt production and < 26.5 pb for s-channel production. For the t-channel measurement, both cut-based and neural network analyses are performed and the cross-section is measured to be 90 +32 -22 pb, where 65 +28 -19 pb is expected according to standard model.