Measurements of $t$-channel single top-quark production cross sections at $\sqrt{s} = 7$ TeV with the ATLAS detector

TL;DR

This paper reports measurements of the $t$-channel single top-quark production cross sections and their ratio at 7 TeV using ATLAS data, employing neural networks for analysis, and finds results consistent with the Standard Model.

Contribution

First measurement of $t$-channel single top-quark cross sections and their ratio at 7 TeV with detailed differential distributions using neural network techniques.

Findings

Cross section for top quark: 46 ± 6 pb

Cross section for top antiquark: 23 ± 4 pb

Ratio of cross sections: 2.04 ± 0.18

Abstract

This article presents measurements of the $t$-channel single top-quark ($t$) and top-antiquark ($\bar{t}$) total production cross sections $\sigma(tq)$ and $\sigma(\bar{t}q)$, their ratio $R_t=\sigma(tq)/\sigma(\bar{t}q)$. Differential cross sections for the $\sigma(tq)$ and $\sigma(\bar{t}q)$ processes are measured as a function of the transverse momentum and the absolute value of the rapidity of ($t$) and ($\bar{t}$), respectively. The analysed data set was recorded with the ATLAS detector and corresponds to an integrated luminosity of 4.59 fb$^{-1}$. The cross sections are measured by performing a binned maximum-likelihood fit to the output distributions of neural networks. The resulting measurements are $\sigma(tq)=46 \pm 6$ pb, $\sigma(\bar{t}q)=23 \pm 4$ pb, $R_t=2.04 \pm 0.18$, consistent with the Standard Model expectation.