Measurement of top quark polarization in top-antitop events from proton-proton collisions at √s = 7 TeV using the ATLAS detector

ATLAS COLLABORATION, G. AAD, M.T. DOVA ET AL

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2013 vol. 111 p. 232002 - 232020

0031-9007

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 αl 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 (CPC) or a CP violating (CPV) production process. The measurements obtained, αlPCPC = −0.035 ± 0.014(stat) ± 0.037(syst) and αlPCPV = 0.020 ± 0.016(stat)+0.013−0.017(syst), are in good agreement with the Standard Model prediction of negligible top quark polarization.