Measurement of Top Quark Polarization in Top-Antitop Events from Proton-Proton Collisions at $\\sqrts$ = 7 TeV Using the ATLAS Detector
Journal
Physical Review Letters
Journal Volume
111
Journal Issue
23
Pages
232002
Date Issued
2013
Author(s)
Abstract
This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4.7 fb(-1) of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √s=7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of α(ℓ)P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, α(ℓ)P(CPC)=-0.035±0.014(stat)±0.037(syst) and α(ℓ)P(CPV)=0.020±0.016(stat)(-0.017)(+0.013)(syst), are in good agreement with the standard model prediction of negligible top quark polarization.
Type
journal article