Measurement of the top quark charge in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper measures the electric charge of the top quark using ATLAS data at 7 TeV, confirming it aligns with the Standard Model and excluding alternative models with a different charge.

Contribution

The study provides a precise measurement of the top quark charge, strongly supporting the Standard Model and ruling out certain exotic quark models.

Findings

Top quark charge measured as 0.64 ± 0.02 (stat) ± 0.08 (syst)

Excludes heavy quark models with charge -4/3 at over 8 sigma significance

Supports the Standard Model top quark charge of +2/3

Abstract

A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb-1 of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 +- 0.02 (stat.) +- 0.08 (syst.) from the charges of the top quark decay products in single lepton ttbar candidate events. This excludes models that propose a heavy quark of electric charge --4/3, instead of the Standard Model top quark, with a significance of more than 8 sigma.