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 sqrt(s)=7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of αℓP, 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, ℓPCPC=−0.035±0.014(stat)±0.037(syst) and ℓPCPV=0.020±0.016(stat)+0.013−0.017(syst), are in good agreement with the standard model prediction of negligible top quark polarization.
Measurement of top quark polarization in top-antitop events from proton-proton collisions at sqrt(s) = 7 TeV using the ATLAS detector
BIANCO, MICHELE;GORINI, Edoardo;PRIMAVERA, Margherita;SPAGNOLO, Stefania Antonia;VENTURA, Andrea
2013-01-01
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 sqrt(s)=7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of αℓP, 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, ℓPCPC=−0.035±0.014(stat)±0.037(syst) and ℓPCPV=0.020±0.016(stat)+0.013−0.017(syst), are in good agreement with the standard model prediction of negligible top quark polarization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
